Pranith Kumar Karampuri
2018-Mar-13 07:28 UTC
[Gluster-users] Expected performance for WORM scenario
On Mon, Mar 12, 2018 at 6:23 PM, Ondrej Valousek < Ondrej.Valousek at s3group.com> wrote:> Hi, > > Gluster will never perform well for small files. > > I believe there is nothing you can do with this. >It is bad compared to a disk filesystem but I believe it is much closer to NFS now. Andreas, Looking at your workload, I am suspecting there to be lot of LOOKUPs which reduce performance. Is it possible to do the following? # gluster volume profile <volname> info incremental #execute your workload # gluster volume profile <volname> info incremental > /path/to/file/that/you/need/to/send/us If the last line in there is LOOKUP, mostly we need to enable nl-cache feature and see how it performs.> Ondrej > > > > *From:* gluster-users-bounces at gluster.org [mailto:gluster-users-bounces@ > gluster.org] *On Behalf Of *Andreas Ericsson > *Sent:* Monday, March 12, 2018 1:47 PM > *To:* Gluster-users at gluster.org > *Subject:* [Gluster-users] Expected performance for WORM scenario > > > > Heya fellas. > > > > I've been struggling quite a lot to get glusterfs to perform even > halfdecently with a write-intensive workload. Testnumbers are from gluster > 3.10.7. > > > > We store a bunch of small files in a doubly-tiered sha1 hash fanout > directory structure. The directories themselves aren't overly full. Most of > the data we write to gluster is "write once, read probably never", so 99% > of all operations are of the write variety. > > > > The network between servers is sound. 10gb network cards run over a 10gb > (doh) switch. iperf reports 9.86Gbit/sec. ping reports a latency of 0.1 - > 0.2 ms. There is no firewall, no packet inspection and no nothing between > the servers, and the 10gb switch is the only path between the two machines, > so traffic isn't going over some 2mbit wifi by accident. > > > > Our main storage has always been really slow (write speed of roughly > 1.5MiB/s), but I had long attributed that to the extremely slow disks we > use to back it, so now that we're expanding I set up a new gluster cluster > with state of the art NVMe SSD drives to boost performance. However, > performance only hopped up to around 2.1MiB/s. Perplexed, I tried it first > with a 3-node cluster using 2GB ramdrives, which got me up to 2.4MiB/s. My > last resort was to use a single node running on ramdisk, just to 100% > exclude any network shenanigans, but the write performance stayed at an > absolutely abysmal 3MiB/s. > > > > Writing straight to (the same) ramdisk gives me "normal" ramdisk speed (I > don't actually remember the numbers, but my test that took 2 minutes with > gluster completed before I had time to blink). Writing straight to the > backing SSD drives gives me a throughput of 96MiB/sec. > > > > The test itself writes 8494 files that I simply took randomly from our > production environment, comprising a total of 63.4MiB (so average file size > is just under 8k. Most are actually close to 4k though, with the occasional > 2-or-so MB file in there. > > > > I have googled and read a *lot* of performance-tuning guides, but the > 3MiB/sec on single-node ramdisk seems to be far beyond the crippling one > can cause by misconfiguration of a single system. > > > > With this in mind; What sort of write performance can one reasonably hope > to get with gluster? Assume a 3-node cluster running on top of (small) > ramdisks on a fast and stable network. Is it just a bad fit for our > workload? > > > > /Andreas > > ----- > > The information contained in this e-mail and in any attachments is confidential and is designated solely for the attention of the intended recipient(s). If you are not an intended recipient, you must not use, disclose, copy, distribute or retain this e-mail or any part thereof. If you have received this e-mail in error, please notify the sender by return e-mail and delete all copies of this e-mail from your computer system(s). Please direct any additional queries to: communications at s3group.com. Thank You. Silicon and Software Systems Limited (S3 Group). Registered in Ireland no. 378073. Registered Office: South County Business Park, Leopardstown, Dublin 18. > > > _______________________________________________ > 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/20180313/0216b919/attachment.html>
Pranith Kumar Karampuri
2018-Mar-13 07:28 UTC
[Gluster-users] Expected performance for WORM scenario
On Tue, Mar 13, 2018 at 12:58 PM, Pranith Kumar Karampuri < pkarampu at redhat.com> wrote:> > > On Mon, Mar 12, 2018 at 6:23 PM, Ondrej Valousek < > Ondrej.Valousek at s3group.com> wrote: > >> Hi, >> >> Gluster will never perform well for small files. >> >> I believe there is nothing you can do with this. >> > > It is bad compared to a disk filesystem but I believe it is much closer to > NFS now. > > Andreas, > Looking at your workload, I am suspecting there to be lot of LOOKUPs > which reduce performance. Is it possible to do the following? > > # gluster volume profile <volname> info incremental > #execute your workload > # gluster volume profile <volname> info incremental > > /path/to/file/that/you/need/to/send/us > > If the last line in there is LOOKUP, mostly we need to enable nl-cache > feature and see how it performs. >Please attach this as extra information along with what Nitya asked in the previous mail.> > >> Ondrej >> >> >> >> *From:* gluster-users-bounces at gluster.org [mailto:gluster-users-bounces@ >> gluster.org] *On Behalf Of *Andreas Ericsson >> *Sent:* Monday, March 12, 2018 1:47 PM >> *To:* Gluster-users at gluster.org >> *Subject:* [Gluster-users] Expected performance for WORM scenario >> >> >> >> Heya fellas. >> >> >> >> I've been struggling quite a lot to get glusterfs to perform even >> halfdecently with a write-intensive workload. Testnumbers are from gluster >> 3.10.7. >> >> >> >> We store a bunch of small files in a doubly-tiered sha1 hash fanout >> directory structure. The directories themselves aren't overly full. Most of >> the data we write to gluster is "write once, read probably never", so 99% >> of all operations are of the write variety. >> >> >> >> The network between servers is sound. 10gb network cards run over a 10gb >> (doh) switch. iperf reports 9.86Gbit/sec. ping reports a latency of 0.1 - >> 0.2 ms. There is no firewall, no packet inspection and no nothing between >> the servers, and the 10gb switch is the only path between the two machines, >> so traffic isn't going over some 2mbit wifi by accident. >> >> >> >> Our main storage has always been really slow (write speed of roughly >> 1.5MiB/s), but I had long attributed that to the extremely slow disks we >> use to back it, so now that we're expanding I set up a new gluster cluster >> with state of the art NVMe SSD drives to boost performance. However, >> performance only hopped up to around 2.1MiB/s. Perplexed, I tried it first >> with a 3-node cluster using 2GB ramdrives, which got me up to 2.4MiB/s. My >> last resort was to use a single node running on ramdisk, just to 100% >> exclude any network shenanigans, but the write performance stayed at an >> absolutely abysmal 3MiB/s. >> >> >> >> Writing straight to (the same) ramdisk gives me "normal" ramdisk speed (I >> don't actually remember the numbers, but my test that took 2 minutes with >> gluster completed before I had time to blink). Writing straight to the >> backing SSD drives gives me a throughput of 96MiB/sec. >> >> >> >> The test itself writes 8494 files that I simply took randomly from our >> production environment, comprising a total of 63.4MiB (so average file size >> is just under 8k. Most are actually close to 4k though, with the occasional >> 2-or-so MB file in there. >> >> >> >> I have googled and read a *lot* of performance-tuning guides, but the >> 3MiB/sec on single-node ramdisk seems to be far beyond the crippling one >> can cause by misconfiguration of a single system. >> >> >> >> With this in mind; What sort of write performance can one reasonably hope >> to get with gluster? Assume a 3-node cluster running on top of (small) >> ramdisks on a fast and stable network. Is it just a bad fit for our >> workload? >> >> >> >> /Andreas >> >> ----- >> >> The information contained in this e-mail and in any attachments is confidential and is designated solely for the attention of the intended recipient(s). If you are not an intended recipient, you must not use, disclose, copy, distribute or retain this e-mail or any part thereof. If you have received this e-mail in error, please notify the sender by return e-mail and delete all copies of this e-mail from your computer system(s). Please direct any additional queries to: communications at s3group.com. Thank You. Silicon and Software Systems Limited (S3 Group). Registered in Ireland no. 378073. Registered Office: South County Business Park, Leopardstown, Dublin 18. >> >> >> _______________________________________________ >> Gluster-users mailing list >> Gluster-users at gluster.org >> http://lists.gluster.org/mailman/listinfo/gluster-users >> > > > > -- > Pranith >-- Pranith -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.gluster.org/pipermail/gluster-users/attachments/20180313/ba51422d/attachment.html>
Ondrej Valousek
2018-Mar-13 08:07 UTC
[Gluster-users] Expected performance for WORM scenario
Well, it might be close to the _synchronous_ nfs, but it is still well behind of
the asynchronous nfs performance.
Simple script (bit extreme I know, but helps to draw the picture):
#!/bin/csh
set HOSTNAME=`/bin/hostname`
set j=1
while ($j <= 7000)
echo ahoj > test.$HOSTNAME.$j
@ j++
end
rm -rf test.$HOSTNAME.*
Takes 9 seconds to execute on the NFS share, but 90 seconds on GlusterFS ? i.e.
10 times slower.
Ondrej
From: Pranith Kumar Karampuri [mailto:pkarampu at redhat.com]
Sent: Tuesday, March 13, 2018 8:28 AM
To: Ondrej Valousek <Ondrej.Valousek at s3group.com>
Cc: Andreas Ericsson <andreas.ericsson at findity.com>; Gluster-users at
gluster.org
Subject: Re: [Gluster-users] Expected performance for WORM scenario
On Mon, Mar 12, 2018 at 6:23 PM, Ondrej Valousek <Ondrej.Valousek at
s3group.com<mailto:Ondrej.Valousek at s3group.com>> wrote:
Hi,
Gluster will never perform well for small files.
I believe there is nothing you can do with this.
It is bad compared to a disk filesystem but I believe it is much closer to NFS
now.
Andreas,
Looking at your workload, I am suspecting there to be lot of LOOKUPs which
reduce performance. Is it possible to do the following?
# gluster volume profile <volname> info incremental
#execute your workload
# gluster volume profile <volname> info incremental >
/path/to/file/that/you/need/to/send/us
If the last line in there is LOOKUP, mostly we need to enable nl-cache feature
and see how it performs.
Ondrej
From: gluster-users-bounces at gluster.org<mailto:gluster-users-bounces at
gluster.org> [mailto:gluster-users-bounces at
gluster.org<mailto:gluster-users-bounces at gluster.org>] On Behalf Of
Andreas Ericsson
Sent: Monday, March 12, 2018 1:47 PM
To: Gluster-users at gluster.org<mailto:Gluster-users at gluster.org>
Subject: [Gluster-users] Expected performance for WORM scenario
Heya fellas.
I've been struggling quite a lot to get glusterfs to perform even
halfdecently with a write-intensive workload. Testnumbers are from gluster
3.10.7.
We store a bunch of small files in a doubly-tiered sha1 hash fanout directory
structure. The directories themselves aren't overly full. Most of the data
we write to gluster is "write once, read probably never", so 99% of
all operations are of the write variety.
The network between servers is sound. 10gb network cards run over a 10gb (doh)
switch. iperf reports 9.86Gbit/sec. ping reports a latency of 0.1 - 0.2 ms.
There is no firewall, no packet inspection and no nothing between the servers,
and the 10gb switch is the only path between the two machines, so traffic
isn't going over some 2mbit wifi by accident.
Our main storage has always been really slow (write speed of roughly 1.5MiB/s),
but I had long attributed that to the extremely slow disks we use to back it, so
now that we're expanding I set up a new gluster cluster with state of the
art NVMe SSD drives to boost performance. However, performance only hopped up to
around 2.1MiB/s. Perplexed, I tried it first with a 3-node cluster using 2GB
ramdrives, which got me up to 2.4MiB/s. My last resort was to use a single node
running on ramdisk, just to 100% exclude any network shenanigans, but the write
performance stayed at an absolutely abysmal 3MiB/s.
Writing straight to (the same) ramdisk gives me "normal" ramdisk speed
(I don't actually remember the numbers, but my test that took 2 minutes with
gluster completed before I had time to blink). Writing straight to the backing
SSD drives gives me a throughput of 96MiB/sec.
The test itself writes 8494 files that I simply took randomly from our
production environment, comprising a total of 63.4MiB (so average file size is
just under 8k. Most are actually close to 4k though, with the occasional 2-or-so
MB file in there.
I have googled and read a *lot* of performance-tuning guides, but the 3MiB/sec
on single-node ramdisk seems to be far beyond the crippling one can cause by
misconfiguration of a single system.
With this in mind; What sort of write performance can one reasonably hope to get
with gluster? Assume a 3-node cluster running on top of (small) ramdisks on a
fast and stable network. Is it just a bad fit for our workload?
/Andreas
-----
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You. Silicon and Software Systems Limited (S3 Group). Registered in Ireland no.
378073. Registered Office: South County Business Park, Leopardstown, Dublin 18.
_______________________________________________
Gluster-users mailing list
Gluster-users at gluster.org<mailto:Gluster-users at gluster.org>
http://lists.gluster.org/mailman/listinfo/gluster-users
--
Pranith
-----
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Business Park, Leopardstown, Dublin 18.
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Pranith Kumar Karampuri
2018-Mar-13 08:10 UTC
[Gluster-users] Expected performance for WORM scenario
On Tue, Mar 13, 2018 at 1:37 PM, Ondrej Valousek < Ondrej.Valousek at s3group.com> wrote:> Well, it might be close to the _*synchronous*_ nfs, but it is still well > behind of the asynchronous nfs performance. > > Simple script (bit extreme I know, but helps to draw the picture): > > > > #!/bin/csh > > > > set HOSTNAME=`/bin/hostname` > > set j=1 > > while ($j <= 7000) > > echo ahoj > test.$HOSTNAME.$j > > @ j++ > > end > > rm -rf test.$HOSTNAME.* > > > > > > Takes 9 seconds to execute on the NFS share, but 90 seconds on GlusterFS ? > i.e. 10 times slower. >Do you have the new features enabled? performance.stat-prefetch=on performance.cache-invalidation=on performance.md-cache-timeout=600 network.inode-lru-limit=50000 performance.nl-cache=on performance.nl-cache-timeout=600 network.inode-lru-limit=50000> > > Ondrej > > > > *From:* Pranith Kumar Karampuri [mailto:pkarampu at redhat.com] > *Sent:* Tuesday, March 13, 2018 8:28 AM > *To:* Ondrej Valousek <Ondrej.Valousek at s3group.com> > *Cc:* Andreas Ericsson <andreas.ericsson at findity.com>; > Gluster-users at gluster.org > *Subject:* Re: [Gluster-users] Expected performance for WORM scenario > > > > > > > > On Mon, Mar 12, 2018 at 6:23 PM, Ondrej Valousek < > Ondrej.Valousek at s3group.com> wrote: > > Hi, > > Gluster will never perform well for small files. > > I believe there is nothing you can do with this. > > > > It is bad compared to a disk filesystem but I believe it is much closer to > NFS now. > > > > Andreas, > > Looking at your workload, I am suspecting there to be lot of LOOKUPs > which reduce performance. Is it possible to do the following? > > > > # gluster volume profile <volname> info incremental > > #execute your workload > > # gluster volume profile <volname> info incremental > > /path/to/file/that/you/need/to/send/us > > > > If the last line in there is LOOKUP, mostly we need to enable nl-cache > feature and see how it performs. > > > > Ondrej > > > > *From:* gluster-users-bounces at gluster.org [mailto:gluster-users-bounces@ > gluster.org] *On Behalf Of *Andreas Ericsson > *Sent:* Monday, March 12, 2018 1:47 PM > *To:* Gluster-users at gluster.org > *Subject:* [Gluster-users] Expected performance for WORM scenario > > > > Heya fellas. > > > > I've been struggling quite a lot to get glusterfs to perform even > halfdecently with a write-intensive workload. Testnumbers are from gluster > 3.10.7. > > > > We store a bunch of small files in a doubly-tiered sha1 hash fanout > directory structure. The directories themselves aren't overly full. Most of > the data we write to gluster is "write once, read probably never", so 99% > of all operations are of the write variety. > > > > The network between servers is sound. 10gb network cards run over a 10gb > (doh) switch. iperf reports 9.86Gbit/sec. ping reports a latency of 0.1 - > 0.2 ms. There is no firewall, no packet inspection and no nothing between > the servers, and the 10gb switch is the only path between the two machines, > so traffic isn't going over some 2mbit wifi by accident. > > > > Our main storage has always been really slow (write speed of roughly > 1.5MiB/s), but I had long attributed that to the extremely slow disks we > use to back it, so now that we're expanding I set up a new gluster cluster > with state of the art NVMe SSD drives to boost performance. However, > performance only hopped up to around 2.1MiB/s. Perplexed, I tried it first > with a 3-node cluster using 2GB ramdrives, which got me up to 2.4MiB/s. My > last resort was to use a single node running on ramdisk, just to 100% > exclude any network shenanigans, but the write performance stayed at an > absolutely abysmal 3MiB/s. > > > > Writing straight to (the same) ramdisk gives me "normal" ramdisk speed (I > don't actually remember the numbers, but my test that took 2 minutes with > gluster completed before I had time to blink). Writing straight to the > backing SSD drives gives me a throughput of 96MiB/sec. > > > > The test itself writes 8494 files that I simply took randomly from our > production environment, comprising a total of 63.4MiB (so average file size > is just under 8k. Most are actually close to 4k though, with the occasional > 2-or-so MB file in there. > > > > I have googled and read a *lot* of performance-tuning guides, but the > 3MiB/sec on single-node ramdisk seems to be far beyond the crippling one > can cause by misconfiguration of a single system. > > > > With this in mind; What sort of write performance can one reasonably hope > to get with gluster? Assume a 3-node cluster running on top of (small) > ramdisks on a fast and stable network. Is it just a bad fit for our > workload? > > > > /Andreas > > ----- > > > > The information contained in this e-mail and in any attachments is confidential and is designated solely for the attention of the intended recipient(s). If you are not an intended recipient, you must not use, disclose, copy, distribute or retain this e-mail or any part thereof. If you have received this e-mail in error, please notify the sender by return e-mail and delete all copies of this e-mail from your computer system(s). Please direct any additional queries to: communications at s3group.com. Thank You. Silicon and Software Systems Limited (S3 Group). Registered in Ireland no. 378073. Registered Office: South County Business Park, Leopardstown, Dublin 18. > > > _______________________________________________ > Gluster-users mailing list > Gluster-users at gluster.org > http://lists.gluster.org/mailman/listinfo/gluster-users > > > > > -- > > Pranith > > ----- > > The information contained in this e-mail and in any attachments is confidential and is designated solely for the attention of the intended recipient(s). If you are not an intended recipient, you must not use, disclose, copy, distribute or retain this e-mail or any part thereof. If you have received this e-mail in error, please notify the sender by return e-mail and delete all copies of this e-mail from your computer system(s). Please direct any additional queries to: communications at s3group.com. Thank You. Silicon and Software Systems Limited (S3 Group). Registered in Ireland no. 378073. Registered Office: South County Business Park, Leopardstown, Dublin 18. > >-- Pranith -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.gluster.org/pipermail/gluster-users/attachments/20180313/f35f4c39/attachment.html>
Andreas Ericsson
2018-Mar-14 09:43 UTC
[Gluster-users] Expected performance for WORM scenario
That seems unlikely. I pre-create the directory layout and then write to directories I know exist. I don't quite understand how any settings at all can reduce performance to 1/5000 of what I get when writing straight to ramdisk though, and especially when running on a single node instead of in a cluster. Has anyone else set this up and managed to get better write performance? On 13 March 2018 at 08:28, Pranith Kumar Karampuri <pkarampu at redhat.com> wrote:> > > On Mon, Mar 12, 2018 at 6:23 PM, Ondrej Valousek < > Ondrej.Valousek at s3group.com> wrote: > >> Hi, >> >> Gluster will never perform well for small files. >> >> I believe there is nothing you can do with this. >> > > It is bad compared to a disk filesystem but I believe it is much closer to > NFS now. > > Andreas, > Looking at your workload, I am suspecting there to be lot of LOOKUPs > which reduce performance. Is it possible to do the following? > > # gluster volume profile <volname> info incremental > #execute your workload > # gluster volume profile <volname> info incremental > > /path/to/file/that/you/need/to/send/us > > If the last line in there is LOOKUP, mostly we need to enable nl-cache > feature and see how it performs. > > >> Ondrej >> >> >> >> *From:* gluster-users-bounces at gluster.org [mailto:gluster-users-bounces@ >> gluster.org] *On Behalf Of *Andreas Ericsson >> *Sent:* Monday, March 12, 2018 1:47 PM >> *To:* Gluster-users at gluster.org >> *Subject:* [Gluster-users] Expected performance for WORM scenario >> >> >> >> Heya fellas. >> >> >> >> I've been struggling quite a lot to get glusterfs to perform even >> halfdecently with a write-intensive workload. Testnumbers are from gluster >> 3.10.7. >> >> >> >> We store a bunch of small files in a doubly-tiered sha1 hash fanout >> directory structure. The directories themselves aren't overly full. Most of >> the data we write to gluster is "write once, read probably never", so 99% >> of all operations are of the write variety. >> >> >> >> The network between servers is sound. 10gb network cards run over a 10gb >> (doh) switch. iperf reports 9.86Gbit/sec. ping reports a latency of 0.1 - >> 0.2 ms. There is no firewall, no packet inspection and no nothing between >> the servers, and the 10gb switch is the only path between the two machines, >> so traffic isn't going over some 2mbit wifi by accident. >> >> >> >> Our main storage has always been really slow (write speed of roughly >> 1.5MiB/s), but I had long attributed that to the extremely slow disks we >> use to back it, so now that we're expanding I set up a new gluster cluster >> with state of the art NVMe SSD drives to boost performance. However, >> performance only hopped up to around 2.1MiB/s. Perplexed, I tried it first >> with a 3-node cluster using 2GB ramdrives, which got me up to 2.4MiB/s. My >> last resort was to use a single node running on ramdisk, just to 100% >> exclude any network shenanigans, but the write performance stayed at an >> absolutely abysmal 3MiB/s. >> >> >> >> Writing straight to (the same) ramdisk gives me "normal" ramdisk speed (I >> don't actually remember the numbers, but my test that took 2 minutes with >> gluster completed before I had time to blink). Writing straight to the >> backing SSD drives gives me a throughput of 96MiB/sec. >> >> >> >> The test itself writes 8494 files that I simply took randomly from our >> production environment, comprising a total of 63.4MiB (so average file size >> is just under 8k. Most are actually close to 4k though, with the occasional >> 2-or-so MB file in there. >> >> >> >> I have googled and read a *lot* of performance-tuning guides, but the >> 3MiB/sec on single-node ramdisk seems to be far beyond the crippling one >> can cause by misconfiguration of a single system. >> >> >> >> With this in mind; What sort of write performance can one reasonably hope >> to get with gluster? Assume a 3-node cluster running on top of (small) >> ramdisks on a fast and stable network. Is it just a bad fit for our >> workload? >> >> >> >> /Andreas >> >> ----- >> >> The information contained in this e-mail and in any attachments is confidential and is designated solely for the attention of the intended recipient(s). If you are not an intended recipient, you must not use, disclose, copy, distribute or retain this e-mail or any part thereof. If you have received this e-mail in error, please notify the sender by return e-mail and delete all copies of this e-mail from your computer system(s). Please direct any additional queries to: communications at s3group.com. Thank You. Silicon and Software Systems Limited (S3 Group). Registered in Ireland no. 378073. Registered Office: South County Business Park, Leopardstown, Dublin 18. >> >> >> _______________________________________________ >> 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/20180314/bb936fdb/attachment.html>
Ondrej Valousek
2018-Mar-14 10:49 UTC
[Gluster-users] Expected performance for WORM scenario
Gluster offers distributed filesystem. It will NEVER perform as good as a local
filesystem because it can?t.
I also believe NFS will always outperform Gluster in certain situations as it
does not have to deal with distributed locks.
It?s also using FUSE which isn?t great performance-wise.
O.
From: Andreas Ericsson [mailto:andreas.ericsson at findity.com]
Sent: Wednesday, March 14, 2018 10:43 AM
To: Pranith Kumar Karampuri <pkarampu at redhat.com>
Cc: Ondrej Valousek <Ondrej.Valousek at s3group.com>; Gluster-users at
gluster.org
Subject: Re: [Gluster-users] Expected performance for WORM scenario
That seems unlikely. I pre-create the directory layout and then write to
directories I know exist.
I don't quite understand how any settings at all can reduce performance to
1/5000 of what I get when writing straight to ramdisk though, and especially
when running on a single node instead of in a cluster. Has anyone else set this
up and managed to get better write performance?
On 13 March 2018 at 08:28, Pranith Kumar Karampuri <pkarampu at
redhat.com<mailto:pkarampu at redhat.com>> wrote:
On Mon, Mar 12, 2018 at 6:23 PM, Ondrej Valousek <Ondrej.Valousek at
s3group.com<mailto:Ondrej.Valousek at s3group.com>> wrote:
Hi,
Gluster will never perform well for small files.
I believe there is nothing you can do with this.
It is bad compared to a disk filesystem but I believe it is much closer to NFS
now.
Andreas,
Looking at your workload, I am suspecting there to be lot of LOOKUPs which
reduce performance. Is it possible to do the following?
# gluster volume profile <volname> info incremental
#execute your workload
# gluster volume profile <volname> info incremental >
/path/to/file/that/you/need/to/send/us
If the last line in there is LOOKUP, mostly we need to enable nl-cache feature
and see how it performs.
Ondrej
From: gluster-users-bounces at gluster.org<mailto:gluster-users-bounces at
gluster.org> [mailto:gluster-users-bounces at
gluster.org<mailto:gluster-users-bounces at gluster.org>] On Behalf Of
Andreas Ericsson
Sent: Monday, March 12, 2018 1:47 PM
To: Gluster-users at gluster.org<mailto:Gluster-users at gluster.org>
Subject: [Gluster-users] Expected performance for WORM scenario
Heya fellas.
I've been struggling quite a lot to get glusterfs to perform even
halfdecently with a write-intensive workload. Testnumbers are from gluster
3.10.7.
We store a bunch of small files in a doubly-tiered sha1 hash fanout directory
structure. The directories themselves aren't overly full. Most of the data
we write to gluster is "write once, read probably never", so 99% of
all operations are of the write variety.
The network between servers is sound. 10gb network cards run over a 10gb (doh)
switch. iperf reports 9.86Gbit/sec. ping reports a latency of 0.1 - 0.2 ms.
There is no firewall, no packet inspection and no nothing between the servers,
and the 10gb switch is the only path between the two machines, so traffic
isn't going over some 2mbit wifi by accident.
Our main storage has always been really slow (write speed of roughly 1.5MiB/s),
but I had long attributed that to the extremely slow disks we use to back it, so
now that we're expanding I set up a new gluster cluster with state of the
art NVMe SSD drives to boost performance. However, performance only hopped up to
around 2.1MiB/s. Perplexed, I tried it first with a 3-node cluster using 2GB
ramdrives, which got me up to 2.4MiB/s. My last resort was to use a single node
running on ramdisk, just to 100% exclude any network shenanigans, but the write
performance stayed at an absolutely abysmal 3MiB/s.
Writing straight to (the same) ramdisk gives me "normal" ramdisk speed
(I don't actually remember the numbers, but my test that took 2 minutes with
gluster completed before I had time to blink). Writing straight to the backing
SSD drives gives me a throughput of 96MiB/sec.
The test itself writes 8494 files that I simply took randomly from our
production environment, comprising a total of 63.4MiB (so average file size is
just under 8k. Most are actually close to 4k though, with the occasional 2-or-so
MB file in there.
I have googled and read a *lot* of performance-tuning guides, but the 3MiB/sec
on single-node ramdisk seems to be far beyond the crippling one can cause by
misconfiguration of a single system.
With this in mind; What sort of write performance can one reasonably hope to get
with gluster? Assume a 3-node cluster running on top of (small) ramdisks on a
fast and stable network. Is it just a bad fit for our workload?
/Andreas
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