Are you sure using conv=sync is what you want? I normally use conv=fdatasync, I'll look up the difference between the two and see if it affects your test. -b ----- Original Message -----> From: "Pat Haley" <phaley at mit.edu> > To: "Pranith Kumar Karampuri" <pkarampu at redhat.com> > Cc: "Ravishankar N" <ravishankar at redhat.com>, gluster-users at gluster.org, "Steve Postma" <SPostma at ztechnet.com>, "Ben > Turner" <bturner at redhat.com> > Sent: Tuesday, May 30, 2017 9:40:34 PM > Subject: Re: [Gluster-users] Slow write times to gluster disk > > > Hi Pranith, > > The "dd" command was: > > dd if=/dev/zero count=4096 bs=1048576 of=zeros.txt conv=sync > > There were 2 instances where dd reported 22 seconds. The output from the > dd tests are in > > http://mseas.mit.edu/download/phaley/GlusterUsers/TestVol/dd_testvol_gluster.txt > > Pat > > On 05/30/2017 09:27 PM, Pranith Kumar Karampuri wrote: > > Pat, > > What is the command you used? As per the following output, it > > seems like at least one write operation took 16 seconds. Which is > > really bad. > > 96.39 1165.10 us 89.00 us*16487014.00 us* 393212 > > WRITE > > > > > > On Tue, May 30, 2017 at 10:36 PM, Pat Haley <phaley at mit.edu > > <mailto:phaley at mit.edu>> wrote: > > > > > > Hi Pranith, > > > > I ran the same 'dd' test both in the gluster test volume and in > > the .glusterfs directory of each brick. The median results (12 dd > > trials in each test) are similar to before > > > > * gluster test volume: 586.5 MB/s > > * bricks (in .glusterfs): 1.4 GB/s > > > > The profile for the gluster test-volume is in > > > > http://mseas.mit.edu/download/phaley/GlusterUsers/TestVol/profile_testvol_gluster.txt > > <http://mseas.mit.edu/download/phaley/GlusterUsers/TestVol/profile_testvol_gluster.txt> > > > > Thanks > > > > Pat > > > > > > > > > > On 05/30/2017 12:10 PM, Pranith Kumar Karampuri wrote: > >> Let's start with the same 'dd' test we were testing with to see, > >> what the numbers are. Please provide profile numbers for the > >> same. From there on we will start tuning the volume to see what > >> we can do. > >> > >> On Tue, May 30, 2017 at 9:16 PM, Pat Haley <phaley at mit.edu > >> <mailto:phaley at mit.edu>> wrote: > >> > >> > >> Hi Pranith, > >> > >> Thanks for the tip. We now have the gluster volume mounted > >> under /home. What tests do you recommend we run? > >> > >> Thanks > >> > >> Pat > >> > >> > >> > >> On 05/17/2017 05:01 AM, Pranith Kumar Karampuri wrote: > >>> > >>> > >>> On Tue, May 16, 2017 at 9:20 PM, Pat Haley <phaley at mit.edu > >>> <mailto:phaley at mit.edu>> wrote: > >>> > >>> > >>> Hi Pranith, > >>> > >>> Sorry for the delay. I never saw received your reply > >>> (but I did receive Ben Turner's follow-up to your > >>> reply). So we tried to create a gluster volume under > >>> /home using different variations of > >>> > >>> gluster volume create test-volume > >>> mseas-data2:/home/gbrick_test_1 > >>> mseas-data2:/home/gbrick_test_2 transport tcp > >>> > >>> However we keep getting errors of the form > >>> > >>> Wrong brick type: transport, use > >>> <HOSTNAME>:<export-dir-abs-path> > >>> > >>> Any thoughts on what we're doing wrong? > >>> > >>> > >>> You should give transport tcp at the beginning I think. > >>> Anyways, transport tcp is the default, so no need to specify > >>> so remove those two words from the CLI. > >>> > >>> > >>> Also do you have a list of the test we should be running > >>> once we get this volume created? Given the time-zone > >>> difference it might help if we can run a small battery > >>> of tests and post the results rather than test-post-new > >>> test-post... . > >>> > >>> > >>> This is the first time I am doing performance analysis on > >>> users as far as I remember. In our team there are separate > >>> engineers who do these tests. Ben who replied earlier is one > >>> such engineer. > >>> > >>> Ben, > >>> Have any suggestions? > >>> > >>> > >>> Thanks > >>> > >>> Pat > >>> > >>> > >>> > >>> On 05/11/2017 12:06 PM, Pranith Kumar Karampuri wrote: > >>>> > >>>> > >>>> On Thu, May 11, 2017 at 9:32 PM, Pat Haley > >>>> <phaley at mit.edu <mailto:phaley at mit.edu>> wrote: > >>>> > >>>> > >>>> Hi Pranith, > >>>> > >>>> The /home partition is mounted as ext4 > >>>> /home ext4 defaults,usrquota,grpquota 1 2 > >>>> > >>>> The brick partitions are mounted ax xfs > >>>> /mnt/brick1 xfs defaults 0 0 > >>>> /mnt/brick2 xfs defaults 0 0 > >>>> > >>>> Will this cause a problem with creating a volume > >>>> under /home? > >>>> > >>>> > >>>> I don't think the bottleneck is disk. You can do the > >>>> same tests you did on your new volume to confirm? > >>>> > >>>> > >>>> Pat > >>>> > >>>> > >>>> > >>>> On 05/11/2017 11:32 AM, Pranith Kumar Karampuri wrote: > >>>>> > >>>>> > >>>>> On Thu, May 11, 2017 at 8:57 PM, Pat Haley > >>>>> <phaley at mit.edu <mailto:phaley at mit.edu>> wrote: > >>>>> > >>>>> > >>>>> Hi Pranith, > >>>>> > >>>>> Unfortunately, we don't have similar hardware > >>>>> for a small scale test. All we have is our > >>>>> production hardware. > >>>>> > >>>>> > >>>>> You said something about /home partition which has > >>>>> lesser disks, we can create plain distribute > >>>>> volume inside one of those directories. After we > >>>>> are done, we can remove the setup. What do you say? > >>>>> > >>>>> > >>>>> Pat > >>>>> > >>>>> > >>>>> > >>>>> > >>>>> On 05/11/2017 07:05 AM, Pranith Kumar > >>>>> Karampuri wrote: > >>>>>> > >>>>>> > >>>>>> On Thu, May 11, 2017 at 2:48 AM, Pat Haley > >>>>>> <phaley at mit.edu <mailto:phaley at mit.edu>> wrote: > >>>>>> > >>>>>> > >>>>>> Hi Pranith, > >>>>>> > >>>>>> Since we are mounting the partitions as > >>>>>> the bricks, I tried the dd test writing > >>>>>> to > >>>>>> <brick-path>/.glusterfs/<file-to-be-removed-after-test>. > >>>>>> The results without oflag=sync were 1.6 > >>>>>> Gb/s (faster than gluster but not as fast > >>>>>> as I was expecting given the 1.2 Gb/s to > >>>>>> the no-gluster area w/ fewer disks). > >>>>>> > >>>>>> > >>>>>> Okay, then 1.6Gb/s is what we need to target > >>>>>> for, considering your volume is just > >>>>>> distribute. Is there any way you can do tests > >>>>>> on similar hardware but at a small scale? > >>>>>> Just so we can run the workload to learn more > >>>>>> about the bottlenecks in the system? We can > >>>>>> probably try to get the speed to 1.2Gb/s on > >>>>>> your /home partition you were telling me > >>>>>> yesterday. Let me know if that is something > >>>>>> you are okay to do. > >>>>>> > >>>>>> > >>>>>> Pat > >>>>>> > >>>>>> > >>>>>> > >>>>>> On 05/10/2017 01:27 PM, Pranith Kumar > >>>>>> Karampuri wrote: > >>>>>>> > >>>>>>> > >>>>>>> On Wed, May 10, 2017 at 10:15 PM, Pat > >>>>>>> Haley <phaley at mit.edu > >>>>>>> <mailto:phaley at mit.edu>> wrote: > >>>>>>> > >>>>>>> > >>>>>>> Hi Pranith, > >>>>>>> > >>>>>>> Not entirely sure (this isn't my > >>>>>>> area of expertise). I'll run your > >>>>>>> answer by some other people who are > >>>>>>> more familiar with this. > >>>>>>> > >>>>>>> I am also uncertain about how to > >>>>>>> interpret the results when we also > >>>>>>> add the dd tests writing to the > >>>>>>> /home area (no gluster, still on the > >>>>>>> same machine) > >>>>>>> > >>>>>>> * dd test without oflag=sync > >>>>>>> (rough average of multiple tests) > >>>>>>> o gluster w/ fuse mount : 570 Mb/s > >>>>>>> o gluster w/ nfs mount: 390 Mb/s > >>>>>>> o nfs (no gluster): 1.2 Gb/s > >>>>>>> * dd test with oflag=sync (rough > >>>>>>> average of multiple tests) > >>>>>>> o gluster w/ fuse mount: 5 Mb/s > >>>>>>> o gluster w/ nfs mount: 200 Mb/s > >>>>>>> o nfs (no gluster): 20 Mb/s > >>>>>>> > >>>>>>> Given that the non-gluster area is a > >>>>>>> RAID-6 of 4 disks while each brick > >>>>>>> of the gluster area is a RAID-6 of > >>>>>>> 32 disks, I would naively expect the > >>>>>>> writes to the gluster area to be > >>>>>>> roughly 8x faster than to the > >>>>>>> non-gluster. > >>>>>>> > >>>>>>> > >>>>>>> I think a better test is to try and > >>>>>>> write to a file using nfs without any > >>>>>>> gluster to a location that is not inside > >>>>>>> the brick but someother location that is > >>>>>>> on same disk(s). If you are mounting the > >>>>>>> partition as the brick, then we can > >>>>>>> write to a file inside .glusterfs > >>>>>>> directory, something like > >>>>>>> <brick-path>/.glusterfs/<file-to-be-removed-after-test>. > >>>>>>> > >>>>>>> > >>>>>>> > >>>>>>> I still think we have a speed issue, > >>>>>>> I can't tell if fuse vs nfs is part > >>>>>>> of the problem. > >>>>>>> > >>>>>>> > >>>>>>> I got interested in the post because I > >>>>>>> read that fuse speed is lesser than nfs > >>>>>>> speed which is counter-intuitive to my > >>>>>>> understanding. So wanted clarifications. > >>>>>>> Now that I got my clarifications where > >>>>>>> fuse outperformed nfs without sync, we > >>>>>>> can resume testing as described above > >>>>>>> and try to find what it is. Based on > >>>>>>> your email-id I am guessing you are from > >>>>>>> Boston and I am from Bangalore so if you > >>>>>>> are okay with doing this debugging for > >>>>>>> multiple days because of timezones, I > >>>>>>> will be happy to help. Please be a bit > >>>>>>> patient with me, I am under a release > >>>>>>> crunch but I am very curious with the > >>>>>>> problem you posted. > >>>>>>> > >>>>>>> Was there anything useful in the > >>>>>>> profiles? > >>>>>>> > >>>>>>> > >>>>>>> Unfortunately profiles didn't help me > >>>>>>> much, I think we are collecting the > >>>>>>> profiles from an active volume, so it > >>>>>>> has a lot of information that is not > >>>>>>> pertaining to dd so it is difficult to > >>>>>>> find the contributions of dd. So I went > >>>>>>> through your post again and found > >>>>>>> something I didn't pay much attention to > >>>>>>> earlier i.e. oflag=sync, so did my own > >>>>>>> tests on my setup with FUSE so sent that > >>>>>>> reply. > >>>>>>> > >>>>>>> > >>>>>>> Pat > >>>>>>> > >>>>>>> > >>>>>>> > >>>>>>> On 05/10/2017 12:15 PM, Pranith > >>>>>>> Kumar Karampuri wrote: > >>>>>>>> Okay good. At least this validates > >>>>>>>> my doubts. Handling O_SYNC in > >>>>>>>> gluster NFS and fuse is a bit > >>>>>>>> different. > >>>>>>>> When application opens a file with > >>>>>>>> O_SYNC on fuse mount then each > >>>>>>>> write syscall has to be written to > >>>>>>>> disk as part of the syscall where > >>>>>>>> as in case of NFS, there is no > >>>>>>>> concept of open. NFS performs write > >>>>>>>> though a handle saying it needs to > >>>>>>>> be a synchronous write, so write() > >>>>>>>> syscall is performed first then it > >>>>>>>> performs fsync(). so an write on an > >>>>>>>> fd with O_SYNC becomes write+fsync. > >>>>>>>> I am suspecting that when multiple > >>>>>>>> threads do this write+fsync() > >>>>>>>> operation on the same file, > >>>>>>>> multiple writes are batched > >>>>>>>> together to be written do disk so > >>>>>>>> the throughput on the disk is > >>>>>>>> increasing is my guess. > >>>>>>>> > >>>>>>>> Does it answer your doubts? > >>>>>>>> > >>>>>>>> On Wed, May 10, 2017 at 9:35 PM, > >>>>>>>> Pat Haley <phaley at mit.edu > >>>>>>>> <mailto:phaley at mit.edu>> wrote: > >>>>>>>> > >>>>>>>> > >>>>>>>> Without the oflag=sync and only > >>>>>>>> a single test of each, the FUSE > >>>>>>>> is going faster than NFS: > >>>>>>>> > >>>>>>>> FUSE: > >>>>>>>> mseas-data2(dri_nascar)% dd > >>>>>>>> if=/dev/zero count=4096 > >>>>>>>> bs=1048576 of=zeros.txt conv=sync > >>>>>>>> 4096+0 records in > >>>>>>>> 4096+0 records out > >>>>>>>> 4294967296 bytes (4.3 GB) > >>>>>>>> copied, 7.46961 s, 575 MB/s > >>>>>>>> > >>>>>>>> > >>>>>>>> NFS > >>>>>>>> mseas-data2(HYCOM)% dd > >>>>>>>> if=/dev/zero count=4096 > >>>>>>>> bs=1048576 of=zeros.txt conv=sync > >>>>>>>> 4096+0 records in > >>>>>>>> 4096+0 records out > >>>>>>>> 4294967296 bytes (4.3 GB) > >>>>>>>> copied, 11.4264 s, 376 MB/s > >>>>>>>> > >>>>>>>> > >>>>>>>> > >>>>>>>> On 05/10/2017 11:53 AM, Pranith > >>>>>>>> Kumar Karampuri wrote: > >>>>>>>>> Could you let me know the > >>>>>>>>> speed without oflag=sync on > >>>>>>>>> both the mounts? No need to > >>>>>>>>> collect profiles. > >>>>>>>>> > >>>>>>>>> On Wed, May 10, 2017 at 9:17 > >>>>>>>>> PM, Pat Haley <phaley at mit.edu > >>>>>>>>> <mailto:phaley at mit.edu>> wrote: > >>>>>>>>> > >>>>>>>>> > >>>>>>>>> Here is what I see now: > >>>>>>>>> > >>>>>>>>> [root at mseas-data2 ~]# > >>>>>>>>> gluster volume info > >>>>>>>>> > >>>>>>>>> Volume Name: data-volume > >>>>>>>>> Type: Distribute > >>>>>>>>> Volume ID: > >>>>>>>>> c162161e-2a2d-4dac-b015-f31fd89ceb18 > >>>>>>>>> Status: Started > >>>>>>>>> Number of Bricks: 2 > >>>>>>>>> Transport-type: tcp > >>>>>>>>> Bricks: > >>>>>>>>> Brick1: > >>>>>>>>> mseas-data2:/mnt/brick1 > >>>>>>>>> Brick2: > >>>>>>>>> mseas-data2:/mnt/brick2 > >>>>>>>>> Options Reconfigured: > >>>>>>>>> diagnostics.count-fop-hits: on > >>>>>>>>> diagnostics.latency-measurement: > >>>>>>>>> on > >>>>>>>>> nfs.exports-auth-enable: on > >>>>>>>>> diagnostics.brick-sys-log-level: > >>>>>>>>> WARNING > >>>>>>>>> performance.readdir-ahead: on > >>>>>>>>> nfs.disable: on > >>>>>>>>> nfs.export-volumes: off > >>>>>>>>> > >>>>>>>>> > >>>>>>>>> > >>>>>>>>> On 05/10/2017 11:44 AM, > >>>>>>>>> Pranith Kumar Karampuri wrote: > >>>>>>>>>> Is this the volume info > >>>>>>>>>> you have? > >>>>>>>>>> > >>>>>>>>>> >/[root at mseas-data2 > >>>>>>>>>> <http://www.gluster.org/mailman/listinfo/gluster-users> > >>>>>>>>>> ~]# gluster volume info > >>>>>>>>>> />//>/Volume Name: > >>>>>>>>>> data-volume />/Type: > >>>>>>>>>> Distribute />/Volume ID: > >>>>>>>>>> c162161e-2a2d-4dac-b015-f31fd89ceb18 > >>>>>>>>>> />/Status: Started />/Number > >>>>>>>>>> of Bricks: 2 > >>>>>>>>>> />/Transport-type: tcp > >>>>>>>>>> />/Bricks: />/Brick1: > >>>>>>>>>> mseas-data2:/mnt/brick1 > >>>>>>>>>> />/Brick2: > >>>>>>>>>> mseas-data2:/mnt/brick2 > >>>>>>>>>> />/Options Reconfigured: > >>>>>>>>>> />/performance.readdir-ahead: > >>>>>>>>>> on />/nfs.disable: on > >>>>>>>>>> />/nfs.export-volumes: off / > >>>>>>>>>> ?I copied this from old > >>>>>>>>>> thread from 2016. This is > >>>>>>>>>> distribute volume. Did > >>>>>>>>>> you change any of the > >>>>>>>>>> options in between? > >>>>>>>>> > >>>>>>>>> -- > >>>>>>>>> > >>>>>>>>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- > >>>>>>>>> Pat Haley > >>>>>>>>> Email:phaley at mit.edu > >>>>>>>>> <mailto:phaley at mit.edu> > >>>>>>>>> Center for Ocean Engineering > >>>>>>>>> Phone: (617) 253-6824 > >>>>>>>>> Dept. of Mechanical Engineering > >>>>>>>>> Fax: (617) 253-8125 > >>>>>>>>> MIT, Room > >>>>>>>>> 5-213http://web.mit.edu/phaley/www/ > >>>>>>>>> 77 Massachusetts Avenue > >>>>>>>>> Cambridge, MA 02139-4301 > >>>>>>>>> > >>>>>>>>> -- > >>>>>>>>> Pranith > >>>>>>>> > >>>>>>>> -- > >>>>>>>> > >>>>>>>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- > >>>>>>>> Pat Haley > >>>>>>>> Email:phaley at mit.edu > >>>>>>>> <mailto:phaley at mit.edu> > >>>>>>>> Center for Ocean Engineering > >>>>>>>> Phone: (617) 253-6824 > >>>>>>>> Dept. of Mechanical Engineering > >>>>>>>> Fax: (617) 253-8125 > >>>>>>>> MIT, Room > >>>>>>>> 5-213http://web.mit.edu/phaley/www/ > >>>>>>>> 77 Massachusetts Avenue > >>>>>>>> Cambridge, MA 02139-4301 > >>>>>>>> > >>>>>>>> -- > >>>>>>>> Pranith > >>>>>>> > >>>>>>> -- > >>>>>>> > >>>>>>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- > >>>>>>> Pat Haley > >>>>>>> Email:phaley at mit.edu > >>>>>>> <mailto:phaley at mit.edu> > >>>>>>> Center for Ocean Engineering Phone: > >>>>>>> (617) 253-6824 > >>>>>>> Dept. of Mechanical Engineering Fax: > >>>>>>> (617) 253-8125 > >>>>>>> MIT, Room > >>>>>>> 5-213http://web.mit.edu/phaley/www/ > >>>>>>> 77 Massachusetts Avenue > >>>>>>> Cambridge, MA 02139-4301 > >>>>>>> > >>>>>>> -- > >>>>>>> Pranith > >>>>>> > >>>>>> -- > >>>>>> > >>>>>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- > >>>>>> Pat Haley > >>>>>> Email:phaley at mit.edu > >>>>>> <mailto:phaley at mit.edu> > >>>>>> Center for Ocean Engineering Phone: > >>>>>> (617) 253-6824 > >>>>>> Dept. of Mechanical Engineering Fax: > >>>>>> (617) 253-8125 > >>>>>> MIT, Room 5-213http://web.mit.edu/phaley/www/ > >>>>>> 77 Massachusetts Avenue > >>>>>> Cambridge, MA 02139-4301 > >>>>>> > >>>>>> -- > >>>>>> Pranith > >>>>> > >>>>> -- > >>>>> > >>>>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- > >>>>> Pat Haley > >>>>> Email:phaley at mit.edu > >>>>> <mailto:phaley at mit.edu> > >>>>> Center for Ocean Engineering Phone: (617) > >>>>> 253-6824 > >>>>> Dept. of Mechanical Engineering Fax: (617) > >>>>> 253-8125 > >>>>> MIT, Room 5-213http://web.mit.edu/phaley/www/ > >>>>> 77 Massachusetts Avenue > >>>>> Cambridge, MA 02139-4301 > >>>>> > >>>>> -- > >>>>> Pranith > >>>> > >>>> -- > >>>> > >>>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- > >>>> Pat Haley Email:phaley at mit.edu > >>>> <mailto:phaley at mit.edu> > >>>> Center for Ocean Engineering Phone: (617) > >>>> 253-6824 > >>>> Dept. of Mechanical Engineering Fax: (617) > >>>> 253-8125 > >>>> MIT, Room 5-213http://web.mit.edu/phaley/www/ > >>>> 77 Massachusetts Avenue > >>>> Cambridge, MA 02139-4301 > >>>> > >>>> -- > >>>> Pranith > >>> > >>> -- > >>> > >>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- > >>> Pat Haley Email:phaley at mit.edu > >>> <mailto:phaley at mit.edu> > >>> Center for Ocean Engineering Phone: (617) 253-6824 > >>> Dept. of Mechanical Engineering Fax: (617) 253-8125 > >>> MIT, Room 5-213http://web.mit.edu/phaley/www/ > >>> 77 Massachusetts Avenue > >>> Cambridge, MA 02139-4301 > >>> > >>> > >>> > >>> > >>> -- > >>> Pranith > >> > >> -- > >> > >> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- > >> Pat Haley Email:phaley at mit.edu > >> <mailto:phaley at mit.edu> > >> Center for Ocean Engineering Phone: (617) 253-6824 > >> Dept. of Mechanical Engineering Fax: (617) 253-8125 > >> MIT, Room 5-213http://web.mit.edu/phaley/www/ > >> 77 Massachusetts Avenue > >> Cambridge, MA 02139-4301 > >> > >> > >> > >> > >> -- > >> Pranith > > > > -- > > > > -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- > > Pat Haley Email:phaley at mit.edu > > <mailto:phaley at mit.edu> > > Center for Ocean Engineering Phone: (617) 253-6824 > > Dept. of Mechanical Engineering Fax: (617) 253-8125 > > MIT, Room 5-213http://web.mit.edu/phaley/www/ > > 77 Massachusetts Avenue > > Cambridge, MA 02139-4301 > > > > > > > > > > -- > > Pranith > > -- > > -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- > Pat Haley Email: phaley at mit.edu > Center for Ocean Engineering Phone: (617) 253-6824 > Dept. of Mechanical Engineering Fax: (617) 253-8125 > MIT, Room 5-213 http://web.mit.edu/phaley/www/ > 77 Massachusetts Avenue > Cambridge, MA 02139-4301 > >
Hi Guys, I was wondering what our next steps should be to solve the slow write times. Recently I was debugging a large code and writing a lot of output at every time step. When I tried writing to our gluster disks, it was taking over a day to do a single time step whereas if I had the same program (same hardware, network) write to our nfs disk the time per time-step was about 45 minutes. What we are shooting for here would be to have similar times to either gluster of nfs. Thanks Pat On 06/02/2017 01:07 AM, Ben Turner wrote:> Are you sure using conv=sync is what you want? I normally use conv=fdatasync, I'll look up the difference between the two and see if it affects your test. > > > -b > > ----- Original Message ----- >> From: "Pat Haley" <phaley at mit.edu> >> To: "Pranith Kumar Karampuri" <pkarampu at redhat.com> >> Cc: "Ravishankar N" <ravishankar at redhat.com>, gluster-users at gluster.org, "Steve Postma" <SPostma at ztechnet.com>, "Ben >> Turner" <bturner at redhat.com> >> Sent: Tuesday, May 30, 2017 9:40:34 PM >> Subject: Re: [Gluster-users] Slow write times to gluster disk >> >> >> Hi Pranith, >> >> The "dd" command was: >> >> dd if=/dev/zero count=4096 bs=1048576 of=zeros.txt conv=sync >> >> There were 2 instances where dd reported 22 seconds. The output from the >> dd tests are in >> >> http://mseas.mit.edu/download/phaley/GlusterUsers/TestVol/dd_testvol_gluster.txt >> >> Pat >> >> On 05/30/2017 09:27 PM, Pranith Kumar Karampuri wrote: >>> Pat, >>> What is the command you used? As per the following output, it >>> seems like at least one write operation took 16 seconds. Which is >>> really bad. >>> 96.39 1165.10 us 89.00 us*16487014.00 us* 393212 >>> WRITE >>> >>> >>> On Tue, May 30, 2017 at 10:36 PM, Pat Haley <phaley at mit.edu >>> <mailto:phaley at mit.edu>> wrote: >>> >>> >>> Hi Pranith, >>> >>> I ran the same 'dd' test both in the gluster test volume and in >>> the .glusterfs directory of each brick. The median results (12 dd >>> trials in each test) are similar to before >>> >>> * gluster test volume: 586.5 MB/s >>> * bricks (in .glusterfs): 1.4 GB/s >>> >>> The profile for the gluster test-volume is in >>> >>> http://mseas.mit.edu/download/phaley/GlusterUsers/TestVol/profile_testvol_gluster.txt >>> <http://mseas.mit.edu/download/phaley/GlusterUsers/TestVol/profile_testvol_gluster.txt> >>> >>> Thanks >>> >>> Pat >>> >>> >>> >>> >>> On 05/30/2017 12:10 PM, Pranith Kumar Karampuri wrote: >>>> Let's start with the same 'dd' test we were testing with to see, >>>> what the numbers are. Please provide profile numbers for the >>>> same. From there on we will start tuning the volume to see what >>>> we can do. >>>> >>>> On Tue, May 30, 2017 at 9:16 PM, Pat Haley <phaley at mit.edu >>>> <mailto:phaley at mit.edu>> wrote: >>>> >>>> >>>> Hi Pranith, >>>> >>>> Thanks for the tip. We now have the gluster volume mounted >>>> under /home. What tests do you recommend we run? >>>> >>>> Thanks >>>> >>>> Pat >>>> >>>> >>>> >>>> On 05/17/2017 05:01 AM, Pranith Kumar Karampuri wrote: >>>>> >>>>> On Tue, May 16, 2017 at 9:20 PM, Pat Haley <phaley at mit.edu >>>>> <mailto:phaley at mit.edu>> wrote: >>>>> >>>>> >>>>> Hi Pranith, >>>>> >>>>> Sorry for the delay. I never saw received your reply >>>>> (but I did receive Ben Turner's follow-up to your >>>>> reply). So we tried to create a gluster volume under >>>>> /home using different variations of >>>>> >>>>> gluster volume create test-volume >>>>> mseas-data2:/home/gbrick_test_1 >>>>> mseas-data2:/home/gbrick_test_2 transport tcp >>>>> >>>>> However we keep getting errors of the form >>>>> >>>>> Wrong brick type: transport, use >>>>> <HOSTNAME>:<export-dir-abs-path> >>>>> >>>>> Any thoughts on what we're doing wrong? >>>>> >>>>> >>>>> You should give transport tcp at the beginning I think. >>>>> Anyways, transport tcp is the default, so no need to specify >>>>> so remove those two words from the CLI. >>>>> >>>>> >>>>> Also do you have a list of the test we should be running >>>>> once we get this volume created? Given the time-zone >>>>> difference it might help if we can run a small battery >>>>> of tests and post the results rather than test-post-new >>>>> test-post... . >>>>> >>>>> >>>>> This is the first time I am doing performance analysis on >>>>> users as far as I remember. In our team there are separate >>>>> engineers who do these tests. Ben who replied earlier is one >>>>> such engineer. >>>>> >>>>> Ben, >>>>> Have any suggestions? >>>>> >>>>> >>>>> Thanks >>>>> >>>>> Pat >>>>> >>>>> >>>>> >>>>> On 05/11/2017 12:06 PM, Pranith Kumar Karampuri wrote: >>>>>> >>>>>> On Thu, May 11, 2017 at 9:32 PM, Pat Haley >>>>>> <phaley at mit.edu <mailto:phaley at mit.edu>> wrote: >>>>>> >>>>>> >>>>>> Hi Pranith, >>>>>> >>>>>> The /home partition is mounted as ext4 >>>>>> /home ext4 defaults,usrquota,grpquota 1 2 >>>>>> >>>>>> The brick partitions are mounted ax xfs >>>>>> /mnt/brick1 xfs defaults 0 0 >>>>>> /mnt/brick2 xfs defaults 0 0 >>>>>> >>>>>> Will this cause a problem with creating a volume >>>>>> under /home? >>>>>> >>>>>> >>>>>> I don't think the bottleneck is disk. You can do the >>>>>> same tests you did on your new volume to confirm? >>>>>> >>>>>> >>>>>> Pat >>>>>> >>>>>> >>>>>> >>>>>> On 05/11/2017 11:32 AM, Pranith Kumar Karampuri wrote: >>>>>>> >>>>>>> On Thu, May 11, 2017 at 8:57 PM, Pat Haley >>>>>>> <phaley at mit.edu <mailto:phaley at mit.edu>> wrote: >>>>>>> >>>>>>> >>>>>>> Hi Pranith, >>>>>>> >>>>>>> Unfortunately, we don't have similar hardware >>>>>>> for a small scale test. All we have is our >>>>>>> production hardware. >>>>>>> >>>>>>> >>>>>>> You said something about /home partition which has >>>>>>> lesser disks, we can create plain distribute >>>>>>> volume inside one of those directories. After we >>>>>>> are done, we can remove the setup. What do you say? >>>>>>> >>>>>>> >>>>>>> Pat >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> On 05/11/2017 07:05 AM, Pranith Kumar >>>>>>> Karampuri wrote: >>>>>>>> >>>>>>>> On Thu, May 11, 2017 at 2:48 AM, Pat Haley >>>>>>>> <phaley at mit.edu <mailto:phaley at mit.edu>> wrote: >>>>>>>> >>>>>>>> >>>>>>>> Hi Pranith, >>>>>>>> >>>>>>>> Since we are mounting the partitions as >>>>>>>> the bricks, I tried the dd test writing >>>>>>>> to >>>>>>>> <brick-path>/.glusterfs/<file-to-be-removed-after-test>. >>>>>>>> The results without oflag=sync were 1.6 >>>>>>>> Gb/s (faster than gluster but not as fast >>>>>>>> as I was expecting given the 1.2 Gb/s to >>>>>>>> the no-gluster area w/ fewer disks). >>>>>>>> >>>>>>>> >>>>>>>> Okay, then 1.6Gb/s is what we need to target >>>>>>>> for, considering your volume is just >>>>>>>> distribute. Is there any way you can do tests >>>>>>>> on similar hardware but at a small scale? >>>>>>>> Just so we can run the workload to learn more >>>>>>>> about the bottlenecks in the system? We can >>>>>>>> probably try to get the speed to 1.2Gb/s on >>>>>>>> your /home partition you were telling me >>>>>>>> yesterday. Let me know if that is something >>>>>>>> you are okay to do. >>>>>>>> >>>>>>>> >>>>>>>> Pat >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> On 05/10/2017 01:27 PM, Pranith Kumar >>>>>>>> Karampuri wrote: >>>>>>>>> >>>>>>>>> On Wed, May 10, 2017 at 10:15 PM, Pat >>>>>>>>> Haley <phaley at mit.edu >>>>>>>>> <mailto:phaley at mit.edu>> wrote: >>>>>>>>> >>>>>>>>> >>>>>>>>> Hi Pranith, >>>>>>>>> >>>>>>>>> Not entirely sure (this isn't my >>>>>>>>> area of expertise). I'll run your >>>>>>>>> answer by some other people who are >>>>>>>>> more familiar with this. >>>>>>>>> >>>>>>>>> I am also uncertain about how to >>>>>>>>> interpret the results when we also >>>>>>>>> add the dd tests writing to the >>>>>>>>> /home area (no gluster, still on the >>>>>>>>> same machine) >>>>>>>>> >>>>>>>>> * dd test without oflag=sync >>>>>>>>> (rough average of multiple tests) >>>>>>>>> o gluster w/ fuse mount : 570 Mb/s >>>>>>>>> o gluster w/ nfs mount: 390 Mb/s >>>>>>>>> o nfs (no gluster): 1.2 Gb/s >>>>>>>>> * dd test with oflag=sync (rough >>>>>>>>> average of multiple tests) >>>>>>>>> o gluster w/ fuse mount: 5 Mb/s >>>>>>>>> o gluster w/ nfs mount: 200 Mb/s >>>>>>>>> o nfs (no gluster): 20 Mb/s >>>>>>>>> >>>>>>>>> Given that the non-gluster area is a >>>>>>>>> RAID-6 of 4 disks while each brick >>>>>>>>> of the gluster area is a RAID-6 of >>>>>>>>> 32 disks, I would naively expect the >>>>>>>>> writes to the gluster area to be >>>>>>>>> roughly 8x faster than to the >>>>>>>>> non-gluster. >>>>>>>>> >>>>>>>>> >>>>>>>>> I think a better test is to try and >>>>>>>>> write to a file using nfs without any >>>>>>>>> gluster to a location that is not inside >>>>>>>>> the brick but someother location that is >>>>>>>>> on same disk(s). If you are mounting the >>>>>>>>> partition as the brick, then we can >>>>>>>>> write to a file inside .glusterfs >>>>>>>>> directory, something like >>>>>>>>> <brick-path>/.glusterfs/<file-to-be-removed-after-test>. >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> I still think we have a speed issue, >>>>>>>>> I can't tell if fuse vs nfs is part >>>>>>>>> of the problem. >>>>>>>>> >>>>>>>>> >>>>>>>>> I got interested in the post because I >>>>>>>>> read that fuse speed is lesser than nfs >>>>>>>>> speed which is counter-intuitive to my >>>>>>>>> understanding. So wanted clarifications. >>>>>>>>> Now that I got my clarifications where >>>>>>>>> fuse outperformed nfs without sync, we >>>>>>>>> can resume testing as described above >>>>>>>>> and try to find what it is. Based on >>>>>>>>> your email-id I am guessing you are from >>>>>>>>> Boston and I am from Bangalore so if you >>>>>>>>> are okay with doing this debugging for >>>>>>>>> multiple days because of timezones, I >>>>>>>>> will be happy to help. Please be a bit >>>>>>>>> patient with me, I am under a release >>>>>>>>> crunch but I am very curious with the >>>>>>>>> problem you posted. >>>>>>>>> >>>>>>>>> Was there anything useful in the >>>>>>>>> profiles? >>>>>>>>> >>>>>>>>> >>>>>>>>> Unfortunately profiles didn't help me >>>>>>>>> much, I think we are collecting the >>>>>>>>> profiles from an active volume, so it >>>>>>>>> has a lot of information that is not >>>>>>>>> pertaining to dd so it is difficult to >>>>>>>>> find the contributions of dd. So I went >>>>>>>>> through your post again and found >>>>>>>>> something I didn't pay much attention to >>>>>>>>> earlier i.e. oflag=sync, so did my own >>>>>>>>> tests on my setup with FUSE so sent that >>>>>>>>> reply. >>>>>>>>> >>>>>>>>> >>>>>>>>> Pat >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> On 05/10/2017 12:15 PM, Pranith >>>>>>>>> Kumar Karampuri wrote: >>>>>>>>>> Okay good. At least this validates >>>>>>>>>> my doubts. Handling O_SYNC in >>>>>>>>>> gluster NFS and fuse is a bit >>>>>>>>>> different. >>>>>>>>>> When application opens a file with >>>>>>>>>> O_SYNC on fuse mount then each >>>>>>>>>> write syscall has to be written to >>>>>>>>>> disk as part of the syscall where >>>>>>>>>> as in case of NFS, there is no >>>>>>>>>> concept of open. NFS performs write >>>>>>>>>> though a handle saying it needs to >>>>>>>>>> be a synchronous write, so write() >>>>>>>>>> syscall is performed first then it >>>>>>>>>> performs fsync(). so an write on an >>>>>>>>>> fd with O_SYNC becomes write+fsync. >>>>>>>>>> I am suspecting that when multiple >>>>>>>>>> threads do this write+fsync() >>>>>>>>>> operation on the same file, >>>>>>>>>> multiple writes are batched >>>>>>>>>> together to be written do disk so >>>>>>>>>> the throughput on the disk is >>>>>>>>>> increasing is my guess. >>>>>>>>>> >>>>>>>>>> Does it answer your doubts? >>>>>>>>>> >>>>>>>>>> On Wed, May 10, 2017 at 9:35 PM, >>>>>>>>>> Pat Haley <phaley at mit.edu >>>>>>>>>> <mailto:phaley at mit.edu>> wrote: >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> Without the oflag=sync and only >>>>>>>>>> a single test of each, the FUSE >>>>>>>>>> is going faster than NFS: >>>>>>>>>> >>>>>>>>>> FUSE: >>>>>>>>>> mseas-data2(dri_nascar)% dd >>>>>>>>>> if=/dev/zero count=4096 >>>>>>>>>> bs=1048576 of=zeros.txt conv=sync >>>>>>>>>> 4096+0 records in >>>>>>>>>> 4096+0 records out >>>>>>>>>> 4294967296 bytes (4.3 GB) >>>>>>>>>> copied, 7.46961 s, 575 MB/s >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> NFS >>>>>>>>>> mseas-data2(HYCOM)% dd >>>>>>>>>> if=/dev/zero count=4096 >>>>>>>>>> bs=1048576 of=zeros.txt conv=sync >>>>>>>>>> 4096+0 records in >>>>>>>>>> 4096+0 records out >>>>>>>>>> 4294967296 bytes (4.3 GB) >>>>>>>>>> copied, 11.4264 s, 376 MB/s >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> On 05/10/2017 11:53 AM, Pranith >>>>>>>>>> Kumar Karampuri wrote: >>>>>>>>>>> Could you let me know the >>>>>>>>>>> speed without oflag=sync on >>>>>>>>>>> both the mounts? No need to >>>>>>>>>>> collect profiles. >>>>>>>>>>> >>>>>>>>>>> On Wed, May 10, 2017 at 9:17 >>>>>>>>>>> PM, Pat Haley <phaley at mit.edu >>>>>>>>>>> <mailto:phaley at mit.edu>> wrote: >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> Here is what I see now: >>>>>>>>>>> >>>>>>>>>>> [root at mseas-data2 ~]# >>>>>>>>>>> gluster volume info >>>>>>>>>>> >>>>>>>>>>> Volume Name: data-volume >>>>>>>>>>> Type: Distribute >>>>>>>>>>> Volume ID: >>>>>>>>>>> c162161e-2a2d-4dac-b015-f31fd89ceb18 >>>>>>>>>>> Status: Started >>>>>>>>>>> Number of Bricks: 2 >>>>>>>>>>> Transport-type: tcp >>>>>>>>>>> Bricks: >>>>>>>>>>> Brick1: >>>>>>>>>>> mseas-data2:/mnt/brick1 >>>>>>>>>>> Brick2: >>>>>>>>>>> mseas-data2:/mnt/brick2 >>>>>>>>>>> Options Reconfigured: >>>>>>>>>>> diagnostics.count-fop-hits: on >>>>>>>>>>> diagnostics.latency-measurement: >>>>>>>>>>> on >>>>>>>>>>> nfs.exports-auth-enable: on >>>>>>>>>>> diagnostics.brick-sys-log-level: >>>>>>>>>>> WARNING >>>>>>>>>>> performance.readdir-ahead: on >>>>>>>>>>> nfs.disable: on >>>>>>>>>>> nfs.export-volumes: off >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> On 05/10/2017 11:44 AM, >>>>>>>>>>> Pranith Kumar Karampuri wrote: >>>>>>>>>>>> Is this the volume info >>>>>>>>>>>> you have? >>>>>>>>>>>> >>>>>>>>>>>> >/[root at mseas-data2 >>>>>>>>>>>> <http://www.gluster.org/mailman/listinfo/gluster-users> >>>>>>>>>>>> ~]# gluster volume info >>>>>>>>>>>> />//>/Volume Name: >>>>>>>>>>>> data-volume />/Type: >>>>>>>>>>>> Distribute />/Volume ID: >>>>>>>>>>>> c162161e-2a2d-4dac-b015-f31fd89ceb18 >>>>>>>>>>>> />/Status: Started />/Number >>>>>>>>>>>> of Bricks: 2 >>>>>>>>>>>> />/Transport-type: tcp >>>>>>>>>>>> />/Bricks: />/Brick1: >>>>>>>>>>>> mseas-data2:/mnt/brick1 >>>>>>>>>>>> />/Brick2: >>>>>>>>>>>> mseas-data2:/mnt/brick2 >>>>>>>>>>>> />/Options Reconfigured: >>>>>>>>>>>> />/performance.readdir-ahead: >>>>>>>>>>>> on />/nfs.disable: on >>>>>>>>>>>> />/nfs.export-volumes: off / >>>>>>>>>>>> ?I copied this from old >>>>>>>>>>>> thread from 2016. This is >>>>>>>>>>>> distribute volume. Did >>>>>>>>>>>> you change any of the >>>>>>>>>>>> options in between? >>>>>>>>>>> -- >>>>>>>>>>> >>>>>>>>>>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- >>>>>>>>>>> Pat Haley >>>>>>>>>>> Email:phaley at mit.edu >>>>>>>>>>> <mailto:phaley at mit.edu> >>>>>>>>>>> Center for Ocean Engineering >>>>>>>>>>> Phone: (617) 253-6824 >>>>>>>>>>> Dept. of Mechanical Engineering >>>>>>>>>>> Fax: (617) 253-8125 >>>>>>>>>>> MIT, Room >>>>>>>>>>> 5-213http://web.mit.edu/phaley/www/ >>>>>>>>>>> 77 Massachusetts Avenue >>>>>>>>>>> Cambridge, MA 02139-4301 >>>>>>>>>>> >>>>>>>>>>> -- >>>>>>>>>>> Pranith >>>>>>>>>> -- >>>>>>>>>> >>>>>>>>>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- >>>>>>>>>> Pat Haley >>>>>>>>>> Email:phaley at mit.edu >>>>>>>>>> <mailto:phaley at mit.edu> >>>>>>>>>> Center for Ocean Engineering >>>>>>>>>> Phone: (617) 253-6824 >>>>>>>>>> Dept. of Mechanical Engineering >>>>>>>>>> Fax: (617) 253-8125 >>>>>>>>>> MIT, Room >>>>>>>>>> 5-213http://web.mit.edu/phaley/www/ >>>>>>>>>> 77 Massachusetts Avenue >>>>>>>>>> Cambridge, MA 02139-4301 >>>>>>>>>> >>>>>>>>>> -- >>>>>>>>>> Pranith >>>>>>>>> -- >>>>>>>>> >>>>>>>>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- >>>>>>>>> Pat Haley >>>>>>>>> Email:phaley at mit.edu >>>>>>>>> <mailto:phaley at mit.edu> >>>>>>>>> Center for Ocean Engineering Phone: >>>>>>>>> (617) 253-6824 >>>>>>>>> Dept. of Mechanical Engineering Fax: >>>>>>>>> (617) 253-8125 >>>>>>>>> MIT, Room >>>>>>>>> 5-213http://web.mit.edu/phaley/www/ >>>>>>>>> 77 Massachusetts Avenue >>>>>>>>> Cambridge, MA 02139-4301 >>>>>>>>> >>>>>>>>> -- >>>>>>>>> Pranith >>>>>>>> -- >>>>>>>> >>>>>>>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- >>>>>>>> Pat Haley >>>>>>>> Email:phaley at mit.edu >>>>>>>> <mailto:phaley at mit.edu> >>>>>>>> Center for Ocean Engineering Phone: >>>>>>>> (617) 253-6824 >>>>>>>> Dept. of Mechanical Engineering Fax: >>>>>>>> (617) 253-8125 >>>>>>>> MIT, Room 5-213http://web.mit.edu/phaley/www/ >>>>>>>> 77 Massachusetts Avenue >>>>>>>> Cambridge, MA 02139-4301 >>>>>>>> >>>>>>>> -- >>>>>>>> Pranith >>>>>>> -- >>>>>>> >>>>>>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- >>>>>>> Pat Haley >>>>>>> Email:phaley at mit.edu >>>>>>> <mailto:phaley at mit.edu> >>>>>>> Center for Ocean Engineering Phone: (617) >>>>>>> 253-6824 >>>>>>> Dept. of Mechanical Engineering Fax: (617) >>>>>>> 253-8125 >>>>>>> MIT, Room 5-213http://web.mit.edu/phaley/www/ >>>>>>> 77 Massachusetts Avenue >>>>>>> Cambridge, MA 02139-4301 >>>>>>> >>>>>>> -- >>>>>>> Pranith >>>>>> -- >>>>>> >>>>>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- >>>>>> Pat Haley Email:phaley at mit.edu >>>>>> <mailto:phaley at mit.edu> >>>>>> Center for Ocean Engineering Phone: (617) >>>>>> 253-6824 >>>>>> Dept. of Mechanical Engineering Fax: (617) >>>>>> 253-8125 >>>>>> MIT, Room 5-213http://web.mit.edu/phaley/www/ >>>>>> 77 Massachusetts Avenue >>>>>> Cambridge, MA 02139-4301 >>>>>> >>>>>> -- >>>>>> Pranith >>>>> -- >>>>> >>>>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- >>>>> Pat Haley Email:phaley at mit.edu >>>>> <mailto:phaley at mit.edu> >>>>> Center for Ocean Engineering Phone: (617) 253-6824 >>>>> Dept. of Mechanical Engineering Fax: (617) 253-8125 >>>>> MIT, Room 5-213http://web.mit.edu/phaley/www/ >>>>> 77 Massachusetts Avenue >>>>> Cambridge, MA 02139-4301 >>>>> >>>>> >>>>> >>>>> >>>>> -- >>>>> Pranith >>>> -- >>>> >>>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- >>>> Pat Haley Email:phaley at mit.edu >>>> <mailto:phaley at mit.edu> >>>> Center for Ocean Engineering Phone: (617) 253-6824 >>>> Dept. of Mechanical Engineering Fax: (617) 253-8125 >>>> MIT, Room 5-213http://web.mit.edu/phaley/www/ >>>> 77 Massachusetts Avenue >>>> Cambridge, MA 02139-4301 >>>> >>>> >>>> >>>> >>>> -- >>>> Pranith >>> -- >>> >>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- >>> Pat Haley Email:phaley at mit.edu >>> <mailto:phaley at mit.edu> >>> Center for Ocean Engineering Phone: (617) 253-6824 >>> Dept. of Mechanical Engineering Fax: (617) 253-8125 >>> MIT, Room 5-213http://web.mit.edu/phaley/www/ >>> 77 Massachusetts Avenue >>> Cambridge, MA 02139-4301 >>> >>> >>> >>> >>> -- >>> Pranith >> -- >> >> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- >> Pat Haley Email: phaley at mit.edu >> Center for Ocean Engineering Phone: (617) 253-6824 >> Dept. of Mechanical Engineering Fax: (617) 253-8125 >> MIT, Room 5-213 http://web.mit.edu/phaley/www/ >> 77 Massachusetts Avenue >> Cambridge, MA 02139-4301 >> >>-- -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Pat Haley Email: phaley at mit.edu Center for Ocean Engineering Phone: (617) 253-6824 Dept. of Mechanical Engineering Fax: (617) 253-8125 MIT, Room 5-213 http://web.mit.edu/phaley/www/ 77 Massachusetts Avenue Cambridge, MA 02139-4301
----- Original Message -----> From: "Pat Haley" <phaley at mit.edu> > To: "Ben Turner" <bturner at redhat.com>, "Pranith Kumar Karampuri" <pkarampu at redhat.com> > Cc: "Ravishankar N" <ravishankar at redhat.com>, gluster-users at gluster.org, "Steve Postma" <SPostma at ztechnet.com> > Sent: Monday, June 12, 2017 2:35:41 PM > Subject: Re: [Gluster-users] Slow write times to gluster disk > > > Hi Guys, > > I was wondering what our next steps should be to solve the slow write times. > > Recently I was debugging a large code and writing a lot of output at > every time step. When I tried writing to our gluster disks, it was > taking over a day to do a single time step whereas if I had the same > program (same hardware, network) write to our nfs disk the time per > time-step was about 45 minutes. What we are shooting for here would be > to have similar times to either gluster of nfs.I can see in your test: http://mseas.mit.edu/download/phaley/GlusterUsers/TestVol/dd_testvol_gluster.txt You averaged ~600 MB / sec(expected for replica 2 with 10G, {~1200 MB / sec} / #replicas{2} = 600). Gluster does client side replication so with replica 2 you will only ever see 1/2 the speed of your slowest part of the stack(NW, disk, RAM, CPU). This is usually NW or disk and 600 is normally a best case. Now in your output I do see the instances where you went down to 200 MB / sec. I can only explain this in three ways: 1. You are not using conv=fdatasync and writes are actually going to page cache and then being flushed to disk. During the fsync the memory is not yet available and the disks are busy flushing dirty pages. 2. Your storage RAID group is shared across multiple LUNS(like in a SAN) and when write times are slow the RAID group is busy serviceing other LUNs. 3. Gluster bug / config issue / some other unknown unknown. So I see 2 issues here: 1. NFS does in 45 minutes what gluster can do in 24 hours. 2. Sometimes your throughput drops dramatically. WRT #1 - have a look at my estimates above. My formula for guestimating gluster perf is: throughput = NIC throughput or storage(whatever is slower) / # replicas * overhead(figure .7 or .8). Also the larger the record size the better for glusterfs mounts, I normally like to be at LEAST 64k up to 1024k: # dd if=/dev/zero of=/gluster-mount/file bs=1024k count=10000 conv=fdatasync WRT #2 - Again, I question your testing and your storage config. Try using conv=fdatasync for your DDs, use a larger record size, and make sure that your back end storage is not causing your slowdowns. Also remember that with replica 2 you will take ~50% hit on writes because the client uses 50% of its bandwidth to write to one replica and 50% to the other. -b> > Thanks > > Pat > > > On 06/02/2017 01:07 AM, Ben Turner wrote: > > Are you sure using conv=sync is what you want? I normally use > > conv=fdatasync, I'll look up the difference between the two and see if it > > affects your test. > > > > > > -b > > > > ----- Original Message ----- > >> From: "Pat Haley" <phaley at mit.edu> > >> To: "Pranith Kumar Karampuri" <pkarampu at redhat.com> > >> Cc: "Ravishankar N" <ravishankar at redhat.com>, gluster-users at gluster.org, > >> "Steve Postma" <SPostma at ztechnet.com>, "Ben > >> Turner" <bturner at redhat.com> > >> Sent: Tuesday, May 30, 2017 9:40:34 PM > >> Subject: Re: [Gluster-users] Slow write times to gluster disk > >> > >> > >> Hi Pranith, > >> > >> The "dd" command was: > >> > >> dd if=/dev/zero count=4096 bs=1048576 of=zeros.txt conv=sync > >> > >> There were 2 instances where dd reported 22 seconds. The output from the > >> dd tests are in > >> > >> http://mseas.mit.edu/download/phaley/GlusterUsers/TestVol/dd_testvol_gluster.txt > >> > >> Pat > >> > >> On 05/30/2017 09:27 PM, Pranith Kumar Karampuri wrote: > >>> Pat, > >>> What is the command you used? As per the following output, it > >>> seems like at least one write operation took 16 seconds. Which is > >>> really bad. > >>> 96.39 1165.10 us 89.00 us*16487014.00 us* 393212 > >>> WRITE > >>> > >>> > >>> On Tue, May 30, 2017 at 10:36 PM, Pat Haley <phaley at mit.edu > >>> <mailto:phaley at mit.edu>> wrote: > >>> > >>> > >>> Hi Pranith, > >>> > >>> I ran the same 'dd' test both in the gluster test volume and in > >>> the .glusterfs directory of each brick. The median results (12 dd > >>> trials in each test) are similar to before > >>> > >>> * gluster test volume: 586.5 MB/s > >>> * bricks (in .glusterfs): 1.4 GB/s > >>> > >>> The profile for the gluster test-volume is in > >>> > >>> http://mseas.mit.edu/download/phaley/GlusterUsers/TestVol/profile_testvol_gluster.txt > >>> <http://mseas.mit.edu/download/phaley/GlusterUsers/TestVol/profile_testvol_gluster.txt> > >>> > >>> Thanks > >>> > >>> Pat > >>> > >>> > >>> > >>> > >>> On 05/30/2017 12:10 PM, Pranith Kumar Karampuri wrote: > >>>> Let's start with the same 'dd' test we were testing with to see, > >>>> what the numbers are. Please provide profile numbers for the > >>>> same. From there on we will start tuning the volume to see what > >>>> we can do. > >>>> > >>>> On Tue, May 30, 2017 at 9:16 PM, Pat Haley <phaley at mit.edu > >>>> <mailto:phaley at mit.edu>> wrote: > >>>> > >>>> > >>>> Hi Pranith, > >>>> > >>>> Thanks for the tip. We now have the gluster volume mounted > >>>> under /home. What tests do you recommend we run? > >>>> > >>>> Thanks > >>>> > >>>> Pat > >>>> > >>>> > >>>> > >>>> On 05/17/2017 05:01 AM, Pranith Kumar Karampuri wrote: > >>>>> > >>>>> On Tue, May 16, 2017 at 9:20 PM, Pat Haley <phaley at mit.edu > >>>>> <mailto:phaley at mit.edu>> wrote: > >>>>> > >>>>> > >>>>> Hi Pranith, > >>>>> > >>>>> Sorry for the delay. I never saw received your reply > >>>>> (but I did receive Ben Turner's follow-up to your > >>>>> reply). So we tried to create a gluster volume under > >>>>> /home using different variations of > >>>>> > >>>>> gluster volume create test-volume > >>>>> mseas-data2:/home/gbrick_test_1 > >>>>> mseas-data2:/home/gbrick_test_2 transport tcp > >>>>> > >>>>> However we keep getting errors of the form > >>>>> > >>>>> Wrong brick type: transport, use > >>>>> <HOSTNAME>:<export-dir-abs-path> > >>>>> > >>>>> Any thoughts on what we're doing wrong? > >>>>> > >>>>> > >>>>> You should give transport tcp at the beginning I think. > >>>>> Anyways, transport tcp is the default, so no need to specify > >>>>> so remove those two words from the CLI. > >>>>> > >>>>> > >>>>> Also do you have a list of the test we should be running > >>>>> once we get this volume created? Given the time-zone > >>>>> difference it might help if we can run a small battery > >>>>> of tests and post the results rather than test-post-new > >>>>> test-post... . > >>>>> > >>>>> > >>>>> This is the first time I am doing performance analysis on > >>>>> users as far as I remember. In our team there are separate > >>>>> engineers who do these tests. Ben who replied earlier is one > >>>>> such engineer. > >>>>> > >>>>> Ben, > >>>>> Have any suggestions? > >>>>> > >>>>> > >>>>> Thanks > >>>>> > >>>>> Pat > >>>>> > >>>>> > >>>>> > >>>>> On 05/11/2017 12:06 PM, Pranith Kumar Karampuri wrote: > >>>>>> > >>>>>> On Thu, May 11, 2017 at 9:32 PM, Pat Haley > >>>>>> <phaley at mit.edu <mailto:phaley at mit.edu>> wrote: > >>>>>> > >>>>>> > >>>>>> Hi Pranith, > >>>>>> > >>>>>> The /home partition is mounted as ext4 > >>>>>> /home ext4 defaults,usrquota,grpquota 1 2 > >>>>>> > >>>>>> The brick partitions are mounted ax xfs > >>>>>> /mnt/brick1 xfs defaults 0 0 > >>>>>> /mnt/brick2 xfs defaults 0 0 > >>>>>> > >>>>>> Will this cause a problem with creating a volume > >>>>>> under /home? > >>>>>> > >>>>>> > >>>>>> I don't think the bottleneck is disk. You can do the > >>>>>> same tests you did on your new volume to confirm? > >>>>>> > >>>>>> > >>>>>> Pat > >>>>>> > >>>>>> > >>>>>> > >>>>>> On 05/11/2017 11:32 AM, Pranith Kumar Karampuri > >>>>>> wrote: > >>>>>>> > >>>>>>> On Thu, May 11, 2017 at 8:57 PM, Pat Haley > >>>>>>> <phaley at mit.edu <mailto:phaley at mit.edu>> wrote: > >>>>>>> > >>>>>>> > >>>>>>> Hi Pranith, > >>>>>>> > >>>>>>> Unfortunately, we don't have similar hardware > >>>>>>> for a small scale test. All we have is our > >>>>>>> production hardware. > >>>>>>> > >>>>>>> > >>>>>>> You said something about /home partition which has > >>>>>>> lesser disks, we can create plain distribute > >>>>>>> volume inside one of those directories. After we > >>>>>>> are done, we can remove the setup. What do you say? > >>>>>>> > >>>>>>> > >>>>>>> Pat > >>>>>>> > >>>>>>> > >>>>>>> > >>>>>>> > >>>>>>> On 05/11/2017 07:05 AM, Pranith Kumar > >>>>>>> Karampuri wrote: > >>>>>>>> > >>>>>>>> On Thu, May 11, 2017 at 2:48 AM, Pat Haley > >>>>>>>> <phaley at mit.edu <mailto:phaley at mit.edu>> wrote: > >>>>>>>> > >>>>>>>> > >>>>>>>> Hi Pranith, > >>>>>>>> > >>>>>>>> Since we are mounting the partitions as > >>>>>>>> the bricks, I tried the dd test writing > >>>>>>>> to > >>>>>>>> <brick-path>/.glusterfs/<file-to-be-removed-after-test>. > >>>>>>>> The results without oflag=sync were 1.6 > >>>>>>>> Gb/s (faster than gluster but not as fast > >>>>>>>> as I was expecting given the 1.2 Gb/s to > >>>>>>>> the no-gluster area w/ fewer disks). > >>>>>>>> > >>>>>>>> > >>>>>>>> Okay, then 1.6Gb/s is what we need to target > >>>>>>>> for, considering your volume is just > >>>>>>>> distribute. Is there any way you can do tests > >>>>>>>> on similar hardware but at a small scale? > >>>>>>>> Just so we can run the workload to learn more > >>>>>>>> about the bottlenecks in the system? We can > >>>>>>>> probably try to get the speed to 1.2Gb/s on > >>>>>>>> your /home partition you were telling me > >>>>>>>> yesterday. Let me know if that is something > >>>>>>>> you are okay to do. > >>>>>>>> > >>>>>>>> > >>>>>>>> Pat > >>>>>>>> > >>>>>>>> > >>>>>>>> > >>>>>>>> On 05/10/2017 01:27 PM, Pranith Kumar > >>>>>>>> Karampuri wrote: > >>>>>>>>> > >>>>>>>>> On Wed, May 10, 2017 at 10:15 PM, Pat > >>>>>>>>> Haley <phaley at mit.edu > >>>>>>>>> <mailto:phaley at mit.edu>> wrote: > >>>>>>>>> > >>>>>>>>> > >>>>>>>>> Hi Pranith, > >>>>>>>>> > >>>>>>>>> Not entirely sure (this isn't my > >>>>>>>>> area of expertise). I'll run your > >>>>>>>>> answer by some other people who are > >>>>>>>>> more familiar with this. > >>>>>>>>> > >>>>>>>>> I am also uncertain about how to > >>>>>>>>> interpret the results when we also > >>>>>>>>> add the dd tests writing to the > >>>>>>>>> /home area (no gluster, still on the > >>>>>>>>> same machine) > >>>>>>>>> > >>>>>>>>> * dd test without oflag=sync > >>>>>>>>> (rough average of multiple tests) > >>>>>>>>> o gluster w/ fuse mount : 570 > >>>>>>>>> Mb/s > >>>>>>>>> o gluster w/ nfs mount: 390 Mb/s > >>>>>>>>> o nfs (no gluster): 1.2 Gb/s > >>>>>>>>> * dd test with oflag=sync (rough > >>>>>>>>> average of multiple tests) > >>>>>>>>> o gluster w/ fuse mount: 5 Mb/s > >>>>>>>>> o gluster w/ nfs mount: 200 Mb/s > >>>>>>>>> o nfs (no gluster): 20 Mb/s > >>>>>>>>> > >>>>>>>>> Given that the non-gluster area is a > >>>>>>>>> RAID-6 of 4 disks while each brick > >>>>>>>>> of the gluster area is a RAID-6 of > >>>>>>>>> 32 disks, I would naively expect the > >>>>>>>>> writes to the gluster area to be > >>>>>>>>> roughly 8x faster than to the > >>>>>>>>> non-gluster. > >>>>>>>>> > >>>>>>>>> > >>>>>>>>> I think a better test is to try and > >>>>>>>>> write to a file using nfs without any > >>>>>>>>> gluster to a location that is not inside > >>>>>>>>> the brick but someother location that is > >>>>>>>>> on same disk(s). If you are mounting the > >>>>>>>>> partition as the brick, then we can > >>>>>>>>> write to a file inside .glusterfs > >>>>>>>>> directory, something like > >>>>>>>>> <brick-path>/.glusterfs/<file-to-be-removed-after-test>. > >>>>>>>>> > >>>>>>>>> > >>>>>>>>> > >>>>>>>>> I still think we have a speed issue, > >>>>>>>>> I can't tell if fuse vs nfs is part > >>>>>>>>> of the problem. > >>>>>>>>> > >>>>>>>>> > >>>>>>>>> I got interested in the post because I > >>>>>>>>> read that fuse speed is lesser than nfs > >>>>>>>>> speed which is counter-intuitive to my > >>>>>>>>> understanding. So wanted clarifications. > >>>>>>>>> Now that I got my clarifications where > >>>>>>>>> fuse outperformed nfs without sync, we > >>>>>>>>> can resume testing as described above > >>>>>>>>> and try to find what it is. Based on > >>>>>>>>> your email-id I am guessing you are from > >>>>>>>>> Boston and I am from Bangalore so if you > >>>>>>>>> are okay with doing this debugging for > >>>>>>>>> multiple days because of timezones, I > >>>>>>>>> will be happy to help. Please be a bit > >>>>>>>>> patient with me, I am under a release > >>>>>>>>> crunch but I am very curious with the > >>>>>>>>> problem you posted. > >>>>>>>>> > >>>>>>>>> Was there anything useful in the > >>>>>>>>> profiles? > >>>>>>>>> > >>>>>>>>> > >>>>>>>>> Unfortunately profiles didn't help me > >>>>>>>>> much, I think we are collecting the > >>>>>>>>> profiles from an active volume, so it > >>>>>>>>> has a lot of information that is not > >>>>>>>>> pertaining to dd so it is difficult to > >>>>>>>>> find the contributions of dd. So I went > >>>>>>>>> through your post again and found > >>>>>>>>> something I didn't pay much attention to > >>>>>>>>> earlier i.e. oflag=sync, so did my own > >>>>>>>>> tests on my setup with FUSE so sent that > >>>>>>>>> reply. > >>>>>>>>> > >>>>>>>>> > >>>>>>>>> Pat > >>>>>>>>> > >>>>>>>>> > >>>>>>>>> > >>>>>>>>> On 05/10/2017 12:15 PM, Pranith > >>>>>>>>> Kumar Karampuri wrote: > >>>>>>>>>> Okay good. At least this validates > >>>>>>>>>> my doubts. Handling O_SYNC in > >>>>>>>>>> gluster NFS and fuse is a bit > >>>>>>>>>> different. > >>>>>>>>>> When application opens a file with > >>>>>>>>>> O_SYNC on fuse mount then each > >>>>>>>>>> write syscall has to be written to > >>>>>>>>>> disk as part of the syscall where > >>>>>>>>>> as in case of NFS, there is no > >>>>>>>>>> concept of open. NFS performs write > >>>>>>>>>> though a handle saying it needs to > >>>>>>>>>> be a synchronous write, so write() > >>>>>>>>>> syscall is performed first then it > >>>>>>>>>> performs fsync(). so an write on an > >>>>>>>>>> fd with O_SYNC becomes write+fsync. > >>>>>>>>>> I am suspecting that when multiple > >>>>>>>>>> threads do this write+fsync() > >>>>>>>>>> operation on the same file, > >>>>>>>>>> multiple writes are batched > >>>>>>>>>> together to be written do disk so > >>>>>>>>>> the throughput on the disk is > >>>>>>>>>> increasing is my guess. > >>>>>>>>>> > >>>>>>>>>> Does it answer your doubts? > >>>>>>>>>> > >>>>>>>>>> On Wed, May 10, 2017 at 9:35 PM, > >>>>>>>>>> Pat Haley <phaley at mit.edu > >>>>>>>>>> <mailto:phaley at mit.edu>> wrote: > >>>>>>>>>> > >>>>>>>>>> > >>>>>>>>>> Without the oflag=sync and only > >>>>>>>>>> a single test of each, the FUSE > >>>>>>>>>> is going faster than NFS: > >>>>>>>>>> > >>>>>>>>>> FUSE: > >>>>>>>>>> mseas-data2(dri_nascar)% dd > >>>>>>>>>> if=/dev/zero count=4096 > >>>>>>>>>> bs=1048576 of=zeros.txt conv=sync > >>>>>>>>>> 4096+0 records in > >>>>>>>>>> 4096+0 records out > >>>>>>>>>> 4294967296 bytes (4.3 GB) > >>>>>>>>>> copied, 7.46961 s, 575 MB/s > >>>>>>>>>> > >>>>>>>>>> > >>>>>>>>>> NFS > >>>>>>>>>> mseas-data2(HYCOM)% dd > >>>>>>>>>> if=/dev/zero count=4096 > >>>>>>>>>> bs=1048576 of=zeros.txt conv=sync > >>>>>>>>>> 4096+0 records in > >>>>>>>>>> 4096+0 records out > >>>>>>>>>> 4294967296 bytes (4.3 GB) > >>>>>>>>>> copied, 11.4264 s, 376 MB/s > >>>>>>>>>> > >>>>>>>>>> > >>>>>>>>>> > >>>>>>>>>> On 05/10/2017 11:53 AM, Pranith > >>>>>>>>>> Kumar Karampuri wrote: > >>>>>>>>>>> Could you let me know the > >>>>>>>>>>> speed without oflag=sync on > >>>>>>>>>>> both the mounts? No need to > >>>>>>>>>>> collect profiles. > >>>>>>>>>>> > >>>>>>>>>>> On Wed, May 10, 2017 at 9:17 > >>>>>>>>>>> PM, Pat Haley <phaley at mit.edu > >>>>>>>>>>> <mailto:phaley at mit.edu>> wrote: > >>>>>>>>>>> > >>>>>>>>>>> > >>>>>>>>>>> Here is what I see now: > >>>>>>>>>>> > >>>>>>>>>>> [root at mseas-data2 ~]# > >>>>>>>>>>> gluster volume info > >>>>>>>>>>> > >>>>>>>>>>> Volume Name: data-volume > >>>>>>>>>>> Type: Distribute > >>>>>>>>>>> Volume ID: > >>>>>>>>>>> c162161e-2a2d-4dac-b015-f31fd89ceb18 > >>>>>>>>>>> Status: Started > >>>>>>>>>>> Number of Bricks: 2 > >>>>>>>>>>> Transport-type: tcp > >>>>>>>>>>> Bricks: > >>>>>>>>>>> Brick1: > >>>>>>>>>>> mseas-data2:/mnt/brick1 > >>>>>>>>>>> Brick2: > >>>>>>>>>>> mseas-data2:/mnt/brick2 > >>>>>>>>>>> Options Reconfigured: > >>>>>>>>>>> diagnostics.count-fop-hits: > >>>>>>>>>>> on > >>>>>>>>>>> diagnostics.latency-measurement: > >>>>>>>>>>> on > >>>>>>>>>>> nfs.exports-auth-enable: on > >>>>>>>>>>> diagnostics.brick-sys-log-level: > >>>>>>>>>>> WARNING > >>>>>>>>>>> performance.readdir-ahead: > >>>>>>>>>>> on > >>>>>>>>>>> nfs.disable: on > >>>>>>>>>>> nfs.export-volumes: off > >>>>>>>>>>> > >>>>>>>>>>> > >>>>>>>>>>> > >>>>>>>>>>> On 05/10/2017 11:44 AM, > >>>>>>>>>>> Pranith Kumar Karampuri > >>>>>>>>>>> wrote: > >>>>>>>>>>>> Is this the volume info > >>>>>>>>>>>> you have? > >>>>>>>>>>>> > >>>>>>>>>>>> >/[root at mseas-data2 > >>>>>>>>>>>> <http://www.gluster.org/mailman/listinfo/gluster-users> > >>>>>>>>>>>> ~]# gluster volume info > >>>>>>>>>>>> />//>/Volume Name: > >>>>>>>>>>>> data-volume />/Type: > >>>>>>>>>>>> Distribute />/Volume ID: > >>>>>>>>>>>> c162161e-2a2d-4dac-b015-f31fd89ceb18 > >>>>>>>>>>>> />/Status: Started > >>>>>>>>>>>> />/Number > >>>>>>>>>>>> of Bricks: 2 > >>>>>>>>>>>> />/Transport-type: tcp > >>>>>>>>>>>> />/Bricks: />/Brick1: > >>>>>>>>>>>> mseas-data2:/mnt/brick1 > >>>>>>>>>>>> />/Brick2: > >>>>>>>>>>>> mseas-data2:/mnt/brick2 > >>>>>>>>>>>> />/Options Reconfigured: > >>>>>>>>>>>> />/performance.readdir-ahead: > >>>>>>>>>>>> on />/nfs.disable: on > >>>>>>>>>>>> />/nfs.export-volumes: off > >>>>>>>>>>>> / > >>>>>>>>>>>> ?I copied this from old > >>>>>>>>>>>> thread from 2016. This is > >>>>>>>>>>>> distribute volume. Did > >>>>>>>>>>>> you change any of the > >>>>>>>>>>>> options in between? > >>>>>>>>>>> -- > >>>>>>>>>>> > >>>>>>>>>>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- > >>>>>>>>>>> Pat Haley > >>>>>>>>>>> Email:phaley at mit.edu > >>>>>>>>>>> <mailto:phaley at mit.edu> > >>>>>>>>>>> Center for Ocean Engineering > >>>>>>>>>>> Phone: (617) 253-6824 > >>>>>>>>>>> Dept. of Mechanical > >>>>>>>>>>> Engineering > >>>>>>>>>>> Fax: (617) 253-8125 > >>>>>>>>>>> MIT, Room > >>>>>>>>>>> 5-213http://web.mit.edu/phaley/www/ > >>>>>>>>>>> 77 Massachusetts Avenue > >>>>>>>>>>> Cambridge, MA 02139-4301 > >>>>>>>>>>> > >>>>>>>>>>> -- > >>>>>>>>>>> Pranith > >>>>>>>>>> -- > >>>>>>>>>> > >>>>>>>>>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- > >>>>>>>>>> Pat Haley > >>>>>>>>>> Email:phaley at mit.edu > >>>>>>>>>> <mailto:phaley at mit.edu> > >>>>>>>>>> Center for Ocean Engineering > >>>>>>>>>> Phone: (617) 253-6824 > >>>>>>>>>> Dept. of Mechanical Engineering > >>>>>>>>>> Fax: (617) 253-8125 > >>>>>>>>>> MIT, Room > >>>>>>>>>> 5-213http://web.mit.edu/phaley/www/ > >>>>>>>>>> 77 Massachusetts Avenue > >>>>>>>>>> Cambridge, MA 02139-4301 > >>>>>>>>>> > >>>>>>>>>> -- > >>>>>>>>>> Pranith > >>>>>>>>> -- > >>>>>>>>> > >>>>>>>>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- > >>>>>>>>> Pat Haley > >>>>>>>>> Email:phaley at mit.edu > >>>>>>>>> <mailto:phaley at mit.edu> > >>>>>>>>> Center for Ocean Engineering > >>>>>>>>> Phone: > >>>>>>>>> (617) 253-6824 > >>>>>>>>> Dept. of Mechanical Engineering > >>>>>>>>> Fax: > >>>>>>>>> (617) 253-8125 > >>>>>>>>> MIT, Room > >>>>>>>>> 5-213http://web.mit.edu/phaley/www/ > >>>>>>>>> 77 Massachusetts Avenue > >>>>>>>>> Cambridge, MA 02139-4301 > >>>>>>>>> > >>>>>>>>> -- > >>>>>>>>> Pranith > >>>>>>>> -- > >>>>>>>> > >>>>>>>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- > >>>>>>>> Pat Haley > >>>>>>>> Email:phaley at mit.edu > >>>>>>>> <mailto:phaley at mit.edu> > >>>>>>>> Center for Ocean Engineering Phone: > >>>>>>>> (617) 253-6824 > >>>>>>>> Dept. of Mechanical Engineering Fax: > >>>>>>>> (617) 253-8125 > >>>>>>>> MIT, Room > >>>>>>>> 5-213http://web.mit.edu/phaley/www/ > >>>>>>>> 77 Massachusetts Avenue > >>>>>>>> Cambridge, MA 02139-4301 > >>>>>>>> > >>>>>>>> -- > >>>>>>>> Pranith > >>>>>>> -- > >>>>>>> > >>>>>>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- > >>>>>>> Pat Haley > >>>>>>> Email:phaley at mit.edu > >>>>>>> <mailto:phaley at mit.edu> > >>>>>>> Center for Ocean Engineering Phone: (617) > >>>>>>> 253-6824 > >>>>>>> Dept. of Mechanical Engineering Fax: (617) > >>>>>>> 253-8125 > >>>>>>> MIT, Room 5-213http://web.mit.edu/phaley/www/ > >>>>>>> 77 Massachusetts Avenue > >>>>>>> Cambridge, MA 02139-4301 > >>>>>>> > >>>>>>> -- > >>>>>>> Pranith > >>>>>> -- > >>>>>> > >>>>>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- > >>>>>> Pat Haley > >>>>>> Email:phaley at mit.edu > >>>>>> <mailto:phaley at mit.edu> > >>>>>> Center for Ocean Engineering Phone: (617) > >>>>>> 253-6824 > >>>>>> Dept. of Mechanical Engineering Fax: (617) > >>>>>> 253-8125 > >>>>>> MIT, Room 5-213http://web.mit.edu/phaley/www/ > >>>>>> 77 Massachusetts Avenue > >>>>>> Cambridge, MA 02139-4301 > >>>>>> > >>>>>> -- > >>>>>> Pranith > >>>>> -- > >>>>> > >>>>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- > >>>>> Pat Haley Email:phaley at mit.edu > >>>>> <mailto:phaley at mit.edu> > >>>>> Center for Ocean Engineering Phone: (617) 253-6824 > >>>>> Dept. of Mechanical Engineering Fax: (617) 253-8125 > >>>>> MIT, Room 5-213http://web.mit.edu/phaley/www/ > >>>>> 77 Massachusetts Avenue > >>>>> Cambridge, MA 02139-4301 > >>>>> > >>>>> > >>>>> > >>>>> > >>>>> -- > >>>>> Pranith > >>>> -- > >>>> > >>>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- > >>>> Pat Haley Email:phaley at mit.edu > >>>> <mailto:phaley at mit.edu> > >>>> Center for Ocean Engineering Phone: (617) 253-6824 > >>>> Dept. of Mechanical Engineering Fax: (617) 253-8125 > >>>> MIT, Room 5-213http://web.mit.edu/phaley/www/ > >>>> 77 Massachusetts Avenue > >>>> Cambridge, MA 02139-4301 > >>>> > >>>> > >>>> > >>>> > >>>> -- > >>>> Pranith > >>> -- > >>> > >>> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- > >>> Pat Haley Email:phaley at mit.edu > >>> <mailto:phaley at mit.edu> > >>> Center for Ocean Engineering Phone: (617) 253-6824 > >>> Dept. of Mechanical Engineering Fax: (617) 253-8125 > >>> MIT, Room 5-213http://web.mit.edu/phaley/www/ > >>> 77 Massachusetts Avenue > >>> Cambridge, MA 02139-4301 > >>> > >>> > >>> > >>> > >>> -- > >>> Pranith > >> -- > >> > >> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- > >> Pat Haley Email: phaley at mit.edu > >> Center for Ocean Engineering Phone: (617) 253-6824 > >> Dept. of Mechanical Engineering Fax: (617) 253-8125 > >> MIT, Room 5-213 http://web.mit.edu/phaley/www/ > >> 77 Massachusetts Avenue > >> Cambridge, MA 02139-4301 > >> > >> > > -- > > -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- > Pat Haley Email: phaley at mit.edu > Center for Ocean Engineering Phone: (617) 253-6824 > Dept. of Mechanical Engineering Fax: (617) 253-8125 > MIT, Room 5-213 http://web.mit.edu/phaley/www/ > 77 Massachusetts Avenue > Cambridge, MA 02139-4301 > >