Hi Pat, I'm assuming you are using gluster native (fuse mount). If it helps, you could try mounting it via gluster NFS (gnfs) and then see if there is an improvement in speed. Fuse mounts are slower than gnfs mounts but you get the benefit of avoiding a single point of failure. Unlike fuse mounts, if the gluster node containing the gnfs server goes down, all mounts done using that node will fail). For fuse mounts, you could try tweaking the write-behind xlator settings to see if it helps. See the performance.write-behind and performance.write-behind-window-size options in `gluster volume set help`. Of course, even for gnfs mounts, you can achieve fail-over by using CTDB. Thanks, Ravi On 04/08/2017 12:07 AM, Pat Haley wrote:> > Hi, > > We noticed a dramatic slowness when writing to a gluster disk when > compared to writing to an NFS disk. Specifically when using dd (data > duplicator) to write a 4.3 GB file of zeros: > > * on NFS disk (/home): 9.5 Gb/s > * on gluster disk (/gdata): 508 Mb/s > > The gluser disk is 2 bricks joined together, no replication or > anything else. The hardware is (literally) the same: > > * one server with 70 hard disks and a hardware RAID card. > * 4 disks in a RAID-6 group (the NFS disk) > * 32 disks in a RAID-6 group (the max allowed by the card, /mnt/brick1) > * 32 disks in another RAID-6 group (/mnt/brick2) > * 2 hot spare > > Some additional information and more tests results (after changing the > log level): > > glusterfs 3.7.11 built on Apr 27 2016 14:09:22 > CentOS release 6.8 (Final) > RAID bus controller: LSI Logic / Symbios Logic MegaRAID SAS-3 3108 > [Invader] (rev 02) > > > > *Create the file to /gdata (gluster)* > [root at mseas-data2 gdata]# dd if=/dev/zero of=/gdata/zero1 bs=1M count=1000 > 1000+0 records in > 1000+0 records out > 1048576000 bytes (1.0 GB) copied, 1.91876 s, *546 MB/s* > > *Create the file to /home (ext4)* > [root at mseas-data2 gdata]# dd if=/dev/zero of=/home/zero1 bs=1M count=1000 > 1000+0 records in > 1000+0 records out > 1048576000 bytes (1.0 GB) copied, 0.686021 s, *1.5 GB/s - *3 times as > fast* > > > Copy from /gdata to /gdata (gluster to gluster) > *[root at mseas-data2 gdata]# dd if=/gdata/zero1 of=/gdata/zero2 > 2048000+0 records in > 2048000+0 records out > 1048576000 bytes (1.0 GB) copied, 101.052 s, *10.4 MB/s* - realllyyy > slooowww > > > *Copy from /gdata to /gdata* *2nd time *(gluster to gluster)** > [root at mseas-data2 gdata]# dd if=/gdata/zero1 of=/gdata/zero2 > 2048000+0 records in > 2048000+0 records out > 1048576000 bytes (1.0 GB) copied, 92.4904 s, *11.3 MB/s* - realllyyy > slooowww again > > > > *Copy from /home to /home (ext4 to ext4)* > [root at mseas-data2 gdata]# dd if=/home/zero1 of=/home/zero2 > 2048000+0 records in > 2048000+0 records out > 1048576000 bytes (1.0 GB) copied, 3.53263 s, *297 MB/s *30 times as fast > > > *Copy from /home to /home (ext4 to ext4)* > [root at mseas-data2 gdata]# dd if=/home/zero1 of=/home/zero3 > 2048000+0 records in > 2048000+0 records out > 1048576000 bytes (1.0 GB) copied, 4.1737 s, *251 MB/s* - 30 times as fast > > > As a test, can we copy data directly to the xfs mountpoint > (/mnt/brick1) and bypass gluster? > > > Any help you could give us would be appreciated. > > Thanks > > -- > > -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- > 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 5-213http://web.mit.edu/phaley/www/ > 77 Massachusetts Avenue > Cambridge, MA 02139-4301 > > > _______________________________________________ > Gluster-users mailing list > Gluster-users at gluster.org > http://lists.gluster.org/mailman/listinfo/gluster-users-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.gluster.org/pipermail/gluster-users/attachments/20170408/5c7a01f4/attachment.html>
Hi Ravi, Thanks for the reply. And yes, we are using the gluster native (fuse) mount. Since this is not my area of expertise I have a few questions (mostly clarifications) Is a factor of 20 slow-down typical when compare a fuse-mounted filesytem versus an NFS-mounted filesystem or should we also be looking for additional issues? (Note the first dd test described below was run on the server that hosts the file-systems so no network communication was involved). You also mention tweaking " write-behind xlator settings". Would you expect better speed improvements from switching the mounting from fuse to gnfs or from tweaking the settings? Also are these mutually exclusive or would the be additional benefits from both switching to gfns and tweaking? My next question is to make sure I'm clear on the comment " if the gluster node containing the gnfs server goes down, all mounts done using that node will fail". If you have 2 servers, each 1 brick in the over-all gluster FS, and one server fails, then for gnfs nothing on either server is visible to other nodes while under fuse only the files on the dead server are not visible. Is this what you meant? Finally, you mention "even for gnfs mounts, you can achieve fail-over by using CTDB". Do you know if CTDB would have any performance impact (i.e. in a worst cast scenario could adding CTDB to gnfs erase the speed benefits of going to gnfs in the first place)? Thanks Pat On 04/08/2017 12:58 AM, Ravishankar N wrote:> Hi Pat, > > I'm assuming you are using gluster native (fuse mount). If it helps, > you could try mounting it via gluster NFS (gnfs) and then see if there > is an improvement in speed. Fuse mounts are slower than gnfs mounts > but you get the benefit of avoiding a single point of failure. Unlike > fuse mounts, if the gluster node containing the gnfs server goes down, > all mounts done using that node will fail). For fuse mounts, you could > try tweaking the write-behind xlator settings to see if it helps. See > the performance.write-behind and performance.write-behind-window-size > options in `gluster volume set help`. Of course, even for gnfs mounts, > you can achieve fail-over by using CTDB. > > Thanks, > Ravi > > On 04/08/2017 12:07 AM, Pat Haley wrote: >> >> Hi, >> >> We noticed a dramatic slowness when writing to a gluster disk when >> compared to writing to an NFS disk. Specifically when using dd (data >> duplicator) to write a 4.3 GB file of zeros: >> >> * on NFS disk (/home): 9.5 Gb/s >> * on gluster disk (/gdata): 508 Mb/s >> >> The gluser disk is 2 bricks joined together, no replication or >> anything else. The hardware is (literally) the same: >> >> * one server with 70 hard disks and a hardware RAID card. >> * 4 disks in a RAID-6 group (the NFS disk) >> * 32 disks in a RAID-6 group (the max allowed by the card, /mnt/brick1) >> * 32 disks in another RAID-6 group (/mnt/brick2) >> * 2 hot spare >> >> Some additional information and more tests results (after changing >> the log level): >> >> glusterfs 3.7.11 built on Apr 27 2016 14:09:22 >> CentOS release 6.8 (Final) >> RAID bus controller: LSI Logic / Symbios Logic MegaRAID SAS-3 3108 >> [Invader] (rev 02) >> >> >> >> *Create the file to /gdata (gluster)* >> [root at mseas-data2 gdata]# dd if=/dev/zero of=/gdata/zero1 bs=1M >> count=1000 >> 1000+0 records in >> 1000+0 records out >> 1048576000 bytes (1.0 GB) copied, 1.91876 s, *546 MB/s* >> >> *Create the file to /home (ext4)* >> [root at mseas-data2 gdata]# dd if=/dev/zero of=/home/zero1 bs=1M count=1000 >> 1000+0 records in >> 1000+0 records out >> 1048576000 bytes (1.0 GB) copied, 0.686021 s, *1.5 GB/s - *3 times as >> fast* >> >> >> Copy from /gdata to /gdata (gluster to gluster) >> *[root at mseas-data2 gdata]# dd if=/gdata/zero1 of=/gdata/zero2 >> 2048000+0 records in >> 2048000+0 records out >> 1048576000 bytes (1.0 GB) copied, 101.052 s, *10.4 MB/s* - realllyyy >> slooowww >> >> >> *Copy from /gdata to /gdata* *2nd time *(gluster to gluster)** >> [root at mseas-data2 gdata]# dd if=/gdata/zero1 of=/gdata/zero2 >> 2048000+0 records in >> 2048000+0 records out >> 1048576000 bytes (1.0 GB) copied, 92.4904 s, *11.3 MB/s* - realllyyy >> slooowww again >> >> >> >> *Copy from /home to /home (ext4 to ext4)* >> [root at mseas-data2 gdata]# dd if=/home/zero1 of=/home/zero2 >> 2048000+0 records in >> 2048000+0 records out >> 1048576000 bytes (1.0 GB) copied, 3.53263 s, *297 MB/s *30 times as fast >> >> >> *Copy from /home to /home (ext4 to ext4)* >> [root at mseas-data2 gdata]# dd if=/home/zero1 of=/home/zero3 >> 2048000+0 records in >> 2048000+0 records out >> 1048576000 bytes (1.0 GB) copied, 4.1737 s, *251 MB/s* - 30 times as fast >> >> >> As a test, can we copy data directly to the xfs mountpoint >> (/mnt/brick1) and bypass gluster? >> >> >> Any help you could give us would be appreciated. >> >> Thanks >> >> -- >> >> -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- >> 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 5-213http://web.mit.edu/phaley/www/ >> 77 Massachusetts Avenue >> Cambridge, MA 02139-4301 >> >> >> _______________________________________________ >> Gluster-users mailing list >> Gluster-users at gluster.org >> http://lists.gluster.org/mailman/listinfo/gluster-users > >-- -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- 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 -------------- next part -------------- An HTML attachment was scrubbed... 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Pranith Kumar Karampuri
2017-Apr-14 06:50 UTC
[Gluster-users] Slow write times to gluster disk
On Sat, Apr 8, 2017 at 10:28 AM, Ravishankar N <ravishankar at redhat.com> wrote:> Hi Pat, > > I'm assuming you are using gluster native (fuse mount). If it helps, you > could try mounting it via gluster NFS (gnfs) and then see if there is an > improvement in speed. Fuse mounts are slower than gnfs mounts but you get > the benefit of avoiding a single point of failure. Unlike fuse mounts, if > the gluster node containing the gnfs server goes down, all mounts done > using that node will fail). For fuse mounts, you could try tweaking the > write-behind xlator settings to see if it helps. See the > performance.write-behind and performance.write-behind-window-size options > in `gluster volume set help`. Of course, even for gnfs mounts, you can > achieve fail-over by using CTDB. >Ravi, Do you have any data that suggests fuse mounts are slower than gNFS servers? Pat, I see that I am late to the thread, but do you happen to have "profile info" of the workload? You can follow https://gluster.readthedocs.io/en/latest/Administrator%20Guide/Monitoring%20Workload/ to get the information.> > Thanks, > Ravi > > > On 04/08/2017 12:07 AM, Pat Haley wrote: > > > Hi, > > We noticed a dramatic slowness when writing to a gluster disk when > compared to writing to an NFS disk. Specifically when using dd (data > duplicator) to write a 4.3 GB file of zeros: > > - on NFS disk (/home): 9.5 Gb/s > - on gluster disk (/gdata): 508 Mb/s > > The gluser disk is 2 bricks joined together, no replication or anything > else. The hardware is (literally) the same: > > - one server with 70 hard disks and a hardware RAID card. > - 4 disks in a RAID-6 group (the NFS disk) > - 32 disks in a RAID-6 group (the max allowed by the card, /mnt/brick1) > - 32 disks in another RAID-6 group (/mnt/brick2) > - 2 hot spare > > Some additional information and more tests results (after changing the log > level): > > glusterfs 3.7.11 built on Apr 27 2016 14:09:22 > CentOS release 6.8 (Final) > RAID bus controller: LSI Logic / Symbios Logic MegaRAID SAS-3 3108 > [Invader] (rev 02) > > > > *Create the file to /gdata (gluster)* > [root at mseas-data2 gdata]# dd if=/dev/zero of=/gdata/zero1 bs=1M count=1000 > 1000+0 records in > 1000+0 records out > 1048576000 bytes (1.0 GB) copied, 1.91876 s, *546 MB/s* > > *Create the file to /home (ext4)* > [root at mseas-data2 gdata]# dd if=/dev/zero of=/home/zero1 bs=1M count=1000 > 1000+0 records in > 1000+0 records out > 1048576000 bytes (1.0 GB) copied, 0.686021 s, *1.5 GB/s - *3 times as fast > > > > * Copy from /gdata to /gdata (gluster to gluster) *[root at mseas-data2 > gdata]# dd if=/gdata/zero1 of=/gdata/zero2 > 2048000+0 records in > 2048000+0 records out > 1048576000 bytes (1.0 GB) copied, 101.052 s, *10.4 MB/s* - realllyyy > slooowww > > > *Copy from /gdata to /gdata* *2nd time (gluster to gluster)* > [root at mseas-data2 gdata]# dd if=/gdata/zero1 of=/gdata/zero2 > 2048000+0 records in > 2048000+0 records out > 1048576000 bytes (1.0 GB) copied, 92.4904 s, *11.3 MB/s* - realllyyy > slooowww again > > > > *Copy from /home to /home (ext4 to ext4)* > [root at mseas-data2 gdata]# dd if=/home/zero1 of=/home/zero2 > 2048000+0 records in > 2048000+0 records out > 1048576000 bytes (1.0 GB) copied, 3.53263 s, *297 MB/s *30 times as fast > > > *Copy from /home to /home (ext4 to ext4)* > [root at mseas-data2 gdata]# dd if=/home/zero1 of=/home/zero3 > 2048000+0 records in > 2048000+0 records out > 1048576000 bytes (1.0 GB) copied, 4.1737 s, *251 MB/s* - 30 times as fast > > > As a test, can we copy data directly to the xfs mountpoint (/mnt/brick1) > and bypass gluster? > > > Any help you could give us would be appreciated. > > Thanks > > -- > > -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- > 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 > > > > _______________________________________________ > Gluster-users mailing listGluster-users at gluster.orghttp://lists.gluster.org/mailman/listinfo/gluster-users > > > > _______________________________________________ > Gluster-users mailing list > Gluster-users at gluster.org > http://lists.gluster.org/mailman/listinfo/gluster-users >-- Pranith -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.gluster.org/pipermail/gluster-users/attachments/20170414/dd3f9839/attachment.html>