[Gluster-users] Expected performance for WORM scenario

Pranith Kumar Karampuri
Tue, 13 Mar 2018 07:28:06 -0000

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>