[Gluster-users] Expected performance for WORM scenario

Wed Mar 14 10:53:31 UTC 2018

If you could replicate the problem you had and provide the volume info +
profile that was requested from the redhat guys that would help in trying
to understand what is happening with your workload. Also if possible the
script you used to generate the load.

We've had our share of difficulties with small files on glusterfs as well.
The last problem we encountered is described here
https://bugzilla.redhat.com/show_bug.cgi?id=1546732 and seems to be a
regression from 3.10 to 3.12, but it is related to stat calls taking a long
time and that could be your problem as well. The diagnostics profile output
would tell us if thats the case.

That being said we've started experimenting with
https://github.com/chrislusf/seaweedfs for some of our small file workload.

2018-03-14 11:31 GMT+01:00 Andreas Ericsson <andreas.ericsson at findity.com>:

> We can't stick to single server because the law. Redundancy is a legal
> requirement for our business.
>
> I'm sort of giving up on gluster though. It would seem a pretty stupid
> content addressable storage would suit our needs better.
>
> On 13 March 2018 at 10:12, Ondrej Valousek <Ondrej.Valousek at s3group.com>
> wrote:
>
>> Yes, I have had this in place already (well except of the negative cache,
>> but enabling that did not make much effect).
>>
>> To me, this is no surprise – nothing can match nfs performance for small
>> files for obvious reasons:
>>
>> 1.       Single server, does not have to deal with distributed locks
>>
>> 2.       Afaik, gluster does not support read/write delegations the same
>> way NFS does.
>>
>> 3.       Glusterfs is FUSE based
>>
>> 4.       Glusterfs does not support async writes
>>
>>
>>
>> Summary: If you do not need to scale out, stick with a single server
>> (+DRBD optionally for HA), it will give you the best performance
>>
>>
>>
>> Ondrej
>>
>>
>>
>>
>>
>> *From:* Pranith Kumar Karampuri [mailto:pkarampu at redhat.com]
>> *Sent:* Tuesday, March 13, 2018 9:10 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 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
>>
>> -----
>>
>>
>>
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>>
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>>
>>
>> --
>>
>> 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
>>
>> -----
>>
>> 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.
>>
>>
>
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