Amar Tumballi Suryanarayan
2019-May-01 12:55 UTC
[Gluster-users] performance - what can I expect
Hi Pascal, Sorry for complete delay in this one. And thanks for testing out in different scenarios. Few questions before others can have a look and advice you. 1. What is the volume info output ? 2. Do you see any concerning logs in glusterfs log files? 3. Please use `gluster volume profile` while running the tests, and that gives a lot of information. 4. Considering you are using glusterfs-6.0, please take statedump of client process (on any node) before and after the test, so we can analyze the latency information of each translators. With these information, I hope we will be in a better state to answer the questions. On Wed, Apr 10, 2019 at 3:45 PM Pascal Suter <pascal.suter at dalco.ch> wrote:> i continued my testing with 5 clients, all attached over 100Gbit/s > omni-path via IP over IB. when i run the same iozone benchmark across > all 5 clients where gluster is mounted using the glusterfs client, i get > an aggretated write throughput of only about 400GB/s and an aggregated > read throughput of 1.5GB/s. Each node was writing a single 200Gb file in > 16MB chunks and the files where distributed across all three bricks on > the server. > > the connection was established over Omnipath for sure, as there is no > other link between the nodes and server. > > i have no clue what i'm doing wrong here. i can't believe that this is a > normal performance people would expect to see from gluster. i guess > nobody would be using it if it was this slow. > > again, when written dreictly to the xfs filesystem on the bricks, i get > over 6GB/s read and write throughput using the same benchmark. > > any advise is appreciated > > cheers > > Pascal > > On 04.04.19 12:03, Pascal Suter wrote: > > I just noticed i left the most important parameters out :) > > > > here's the write command with filesize and recordsize in it as well :) > > > > ./iozone -i 0 -t 1 -F /mnt/gluster/storage/thread1 -+n -c -C -e -I -w > > -+S 0 -s 200G -r 16384k > > > > also i ran the benchmark without direct_io which resulted in an even > > worse performance. > > > > i also tried to mount the gluster volume via nfs-ganesha which further > > reduced throughput down to about 450MB/s > > > > if i run the iozone benchmark with 3 threads writing to all three > > bricks directly (from the xfs filesystem) i get throughputs of around > > 6GB/s .. if I run the same benchmark through gluster mounted locally > > using the fuse client and with enough threads so that each brick gets > > at least one file written to it, i end up seing throughputs around > > 1.5GB/s .. that's a 4x decrease in performance. at it actually is the > > same if i run the benchmark with less threads and files only get > > written to two out of three bricks. > > > > cpu load on the server is around 25% by the way, nicely distributed > > across all available cores. > > > > i can't believe that gluster should really be so slow and everybody is > > just happily using it. any hints on what i'm doing wrong are very > > welcome. > > > > i'm using gluster 6.0 by the way. > > > > regards > > > > Pascal > > > > On 03.04.19 12:28, Pascal Suter wrote: > >> Hi all > >> > >> I am currently testing gluster on a single server. I have three > >> bricks, each a hardware RAID6 volume with thin provisioned LVM that > >> was aligned to the RAID and then formatted with xfs. > >> > >> i've created a distributed volume so that entire files get > >> distributed across my three bricks. > >> > >> first I ran a iozone benchmark across each brick testing the read and > >> write perofrmance of a single large file per brick > >> > >> i then mounted my gluster volume locally and ran another iozone run > >> with the same parameters writing a single file. the file went to > >> brick 1 which, when used driectly, would write with 2.3GB/s and read > >> with 1.5GB/s. however, through gluster i got only 800MB/s read and > >> 750MB/s write throughput > >> > >> another run with two processes each writing a file, where one file > >> went to the first brick and the other file to the second brick (which > >> by itself when directly accessed wrote at 2.8GB/s and read at > >> 2.7GB/s) resulted in 1.2GB/s of aggregated write and also aggregated > >> read throughput. > >> > >> Is this a normal performance i can expect out of a glusterfs or is it > >> worth tuning in order to really get closer to the actual brick > >> filesystem performance? > >> > >> here are the iozone commands i use for writing and reading.. note > >> that i am using directIO in order to make sure i don't get fooled by > >> cache :) > >> > >> ./iozone -i 0 -t 1 -F /mnt/brick${b}/thread1 -+n -c -C -e -I -w -+S 0 > >> -s $filesize -r $recordsize > iozone-brick${b}-write.txt > >> > >> ./iozone -i 1 -t 1 -F /mnt/brick${b}/thread1 -+n -c -C -e -I -w -+S 0 > >> -s $filesize -r $recordsize > iozone-brick${b}-read.txt > >> > >> cheers > >> > >> Pascal > >> > >> _______________________________________________ > >> Gluster-users mailing list > >> Gluster-users at gluster.org > >> https://lists.gluster.org/mailman/listinfo/gluster-users > > _______________________________________________ > > Gluster-users mailing list > > Gluster-users at gluster.org > > https://lists.gluster.org/mailman/listinfo/gluster-users > _______________________________________________ > Gluster-users mailing list > Gluster-users at gluster.org > https://lists.gluster.org/mailman/listinfo/gluster-users > > >-- Amar Tumballi (amarts) -------------- next part -------------- An HTML attachment was scrubbed... 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Hi Amar thanks for rolling this back up. Actually i have done some more benchmarking and fiddled with the config to finally reach a performance figure i could live with. I now can squeeze about 3GB/s out of that server which seems to be close to what i can get out of its network uplink (using IP over Omni-Path). The system is now set up and in production so i can't run any benchmarks on it anymore but i will get back at benchmarking in the near future to test some storage related hardware, and i will try it with gluster on top again. embarassingly the biggest performance issue was that the default installation of the server was running the "performance" profile of tuned. once i switched it to "throughput-performance" performance increased dramatically. the volume info now looks pretty unspectacular: Volume Name: storage Type: Distribute Volume ID: c81c7e46-add5-4d88-9945-24cf7947ef8c Status: Started Snapshot Count: 0 Number of Bricks: 3 Transport-type: tcp Bricks: Brick1: themis01:/data/brick1/brick Brick2: themis01:/data/brick2/brick Brick3: themis01:/data/brick3/brick Options Reconfigured: transport.address-family: inet nfs.disable: on thanks for pointing out gluster volume profile, i'll have a go with it during my next benchmarking session. so far i was using iostat to track brick-level io performance during my benchmarks. the main question i wanted to ask was, if there is a general rule of thumb, how much throughput of the original bare brick throughput would be expected to be left over once gluster is added on top of it. to give you an example: when I use a parallel filesystem like Lustre or BeeGFS i usually expect to get at least about 85% of the raw storage target throughput as aggregated bandwidth over a multi-node test out of my Lustre or BeeGFS setup. I consider any numbers below that to be too low and therefore will have to dig into performance tuning to find the bottle neck. i was hoping someone could give me a rule-of-thumb number for a simple distributed gluster setup, like that 85% number i've established for a parallel file system. so at the moment my takeaway is, in a simple distributed volume across 3 bricks with an aggregated bandwidth of 6GB/s i can expect to get about 3GB/s aggregated bandwith out of the gluster mount, given there are no bottle necks in the network. the 3GB/s is a number conducted under ideal circumstances, meaning, i primed the storage to make sure i could run a benchmark run using three nodes, with each node running a single thread writing to a single file and each file was located on another bricke. this yielded the maximum perfomance as this was pure streaming IO without any overlapping file writing to the bricks other than the overhead created by gluster's own internal mechanisms. Interestingly, the performance didn't drop much when i added nodes and threads and introduced more random-ish io by having several processes write to the same brick. So I assume, what "eats" up the 50% performance in the end is probably Gluster writing all these additional hidden files which I assume is some sort of Metadata. This causes additional IO on the disk that i'm streaming my one file to and therefore turns my streaming IO into a random io load for the raid controller and underlying harddisks which on spinning disks would have about the performance impact i was seing in my benchmarks. I have yet to try gluster on a Flash based brick and test its performance there.. i would expect to see a better "efficiency" than the 50% i've measured on this system here as random io vs. streaming io should not make such a difference (or acutally almost no difference at all) on a flash based storage. but that's? me guessing now. so for the moment i'm fine but i would still be interested in hearing ball-park figure "efficiency" numbers from others using gluster in a similar setup. cheers Pascal On 01.05.19 14:55, Amar Tumballi Suryanarayan wrote:> Hi Pascal, > > Sorry for complete delay in this one. And thanks for testing out in > different scenarios.? Few questions before others can have a look and > advice you. > > 1. What is the volume info output ? > > 2. Do you see any concerning logs in glusterfs log files? > > 3. Please use `gluster volume profile` while running the tests, and > that gives a lot of information. > > 4. Considering you are using glusterfs-6.0, please take statedump of > client process (on any node) before and after the test, so we can > analyze the latency information of each translators. > > With these information, I hope we will be in a better state to answer > the questions. > > > On Wed, Apr 10, 2019 at 3:45 PM Pascal Suter <pascal.suter at dalco.ch > <mailto:pascal.suter at dalco.ch>> wrote: > > i continued my testing with 5 clients, all attached over 100Gbit/s > omni-path via IP over IB. when i run the same iozone benchmark across > all 5 clients where gluster is mounted using the glusterfs client, > i get > an aggretated write throughput of only about 400GB/s and an > aggregated > read throughput of 1.5GB/s. Each node was writing a single 200Gb > file in > 16MB chunks and the files where distributed across all three > bricks on > the server. > > the connection was established over Omnipath for sure, as there is no > other link between the nodes and server. > > i have no clue what i'm doing wrong here. i can't believe that > this is a > normal performance people would expect to see from gluster. i guess > nobody would be using it if it was this slow. > > again, when written dreictly to the xfs filesystem on the bricks, > i get > over 6GB/s read and write throughput using the same benchmark. > > any advise is appreciated > > cheers > > Pascal > > On 04.04.19 12:03, Pascal Suter wrote: > > I just noticed i left the most important parameters out :) > > > > here's the write command with filesize and recordsize in it as > well :) > > > > ./iozone -i 0 -t 1 -F /mnt/gluster/storage/thread1 -+n -c -C -e > -I -w > > -+S 0 -s 200G -r 16384k > > > > also i ran the benchmark without direct_io which resulted in an > even > > worse performance. > > > > i also tried to mount the gluster volume via nfs-ganesha which > further > > reduced throughput down to about 450MB/s > > > > if i run the iozone benchmark with 3 threads writing to all three > > bricks directly (from the xfs filesystem) i get throughputs of > around > > 6GB/s .. if I run the same benchmark through gluster mounted > locally > > using the fuse client and with enough threads so that each brick > gets > > at least one file written to it, i end up seing throughputs around > > 1.5GB/s .. that's a 4x decrease in performance. at it actually > is the > > same if i run the benchmark with less threads and files only get > > written to two out of three bricks. > > > > cpu load on the server is around 25% by the way, nicely distributed > > across all available cores. > > > > i can't believe that gluster should really be so slow and > everybody is > > just happily using it. any hints on what i'm doing wrong are very > > welcome. > > > > i'm using gluster 6.0 by the way. > > > > regards > > > > Pascal > > > > On 03.04.19 12:28, Pascal Suter wrote: > >> Hi all > >> > >> I am currently testing gluster on a single server. I have three > >> bricks, each a hardware RAID6 volume with thin provisioned LVM > that > >> was aligned to the RAID and then formatted with xfs. > >> > >> i've created a distributed volume so that entire files get > >> distributed across my three bricks. > >> > >> first I ran a iozone benchmark across each brick testing the > read and > >> write perofrmance of a single large file per brick > >> > >> i then mounted my gluster volume locally and ran another iozone > run > >> with the same parameters writing a single file. the file went to > >> brick 1 which, when used driectly, would write with 2.3GB/s and > read > >> with 1.5GB/s. however, through gluster i got only 800MB/s read and > >> 750MB/s write throughput > >> > >> another run with two processes each writing a file, where one file > >> went to the first brick and the other file to the second brick > (which > >> by itself when directly accessed wrote at 2.8GB/s and read at > >> 2.7GB/s) resulted in 1.2GB/s of aggregated write and also > aggregated > >> read throughput. > >> > >> Is this a normal performance i can expect out of a glusterfs or > is it > >> worth tuning in order to really get closer to the actual brick > >> filesystem performance? > >> > >> here are the iozone commands i use for writing and reading.. note > >> that i am using directIO in order to make sure i don't get > fooled by > >> cache :) > >> > >> ./iozone -i 0 -t 1 -F /mnt/brick${b}/thread1 -+n -c -C -e -I -w > -+S 0 > >> -s $filesize -r $recordsize > iozone-brick${b}-write.txt > >> > >> ./iozone -i 1 -t 1 -F /mnt/brick${b}/thread1 -+n -c -C -e -I -w > -+S 0 > >> -s $filesize -r $recordsize > iozone-brick${b}-read.txt > >> > >> cheers > >> > >> Pascal > >> > >> _______________________________________________ > >> Gluster-users mailing list > >> Gluster-users at gluster.org <mailto:Gluster-users at gluster.org> > >> https://lists.gluster.org/mailman/listinfo/gluster-users > > _______________________________________________ > > Gluster-users mailing list > > Gluster-users at gluster.org <mailto:Gluster-users at gluster.org> > > https://lists.gluster.org/mailman/listinfo/gluster-users > _______________________________________________ > Gluster-users mailing list > Gluster-users at gluster.org <mailto:Gluster-users at gluster.org> > https://lists.gluster.org/mailman/listinfo/gluster-users > > > > > -- > Amar Tumballi (amarts)-------------- next part -------------- An HTML attachment was scrubbed... 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