[Gluster-users] Gluster Performance Issues

Tue Mar 10 20:31:45 UTC 2020

Dear Strahil,

thank you very much for your response. After some testing,

the brick performance was much lower than expected. A previous
benchmarking procedure

at the beginning does not point that out. In our case with real life
data, even with a minor

number of directories and files, a simple ls -l command on the **brick**
itself

take up to 16 seconds (4 seconds in general, but 16s was the worst case
we observed).

We decided to reconfigure the bricks from raid6 to raid10

using the reset-brick command, see section 11.9.5 as reference:

https://access.redhat.com/documentation/en-us/red_hat_gluster_storage/3.5/html/administration_guide/sect-migrating_volumes#sect-Migrating_Volumes-Reconfigure_Brick

This re-configuring worked perfect and self-healing is almost done now
(b.t.w. 2TB/day self-healing performance is normal?).

Since the bricks shows acceptable raid10 performance (at least for our
current workload), the performance on the fuse-mountpoint

on the dispersed volume (4+2) is lower than the brick performance. Maybe
I am wrong, I was going to expect at least

a slightly higher performance than the brick-performance.

Other example:

Just for testing purposes, I created a distributed volume (sharding on)
on the some storage nodes that consists of 2 NVME's / per node (i.e.  6
in total).

A simple rsync command of a single large file provides  222.25M
bytes/sec on a fuse-mount-point of this distributed volume.

The same command, executed on the brick itself provides 265.19M
bytes/sec. As before,

the performance is lower than the individual brick performance. Is this
a normal behavior or

or what can be done to improve the single client performance as pointed
out in this case?

Regards,

Felix

On 20/02/2020 22:26, Strahil Nikolov wrote:
> On February 20, 2020 10:39:47 PM GMT+02:00, "Felix Kölzow" <felix.koelzow at gmx.de> wrote:
>> Dear Gluster-Experts,
>>
>>
>> we created a three-node setup with two bricks each and a dispersed
>> volume that can be
>>
>> accessed via the native client (glusterfs --version = 6.0).
>>
>>
>> The nodes are connected via 10Gbps (cat6,bonding mode 6).
>>
>>
>> If we running a performance test using the smallfile benchmark tool,
>>
>> ./smallfile_cli.py --top ~/test6/ --file-size 16384 --threads 8 --files
>> 1000 --response-times y --operation create
>>
>> we observing the
>>
>> behavior as  shown in the attached figure. For a short time, we can
>> almost saturated the 10Gbps but
>>
>> then immediately network traffic is dropping almost to zero for about 5
>> to 25 seconds.
>>
>> Actually, we don't have any glue what does causes this strange
>> behavior.
>> We had a lot of
>>
>> reconfigured volume options and now we are starting from scratch, i.e.
>>
>>
>> gluster volume reset dispersed_fuse all
>>
>>
>> and the current options looks like:
>>
>> Volume Name: dispersed_fuse
>> Type: Disperse
>> Volume ID: 45d3c7c9-526f-45ea-9930-ee7a2274a220
>> Status: Started
>> Snapshot Count: 1
>> Number of Bricks: 1 x (4 + 2) = 6
>> Transport-type: tcp
>> Bricks:
>> Brick1: mimas:/gluster/vg00/dispersed_fuse/brick
>> Brick2: enceladus:/gluster/vg00/dispersed_fuse/brick
>> Brick3: tethys:/gluster/vg00/dispersed_fuse/brick
>> Brick4: mimas:/gluster/vg01/dispersed_fuse/brick
>> Brick5: enceladus:/gluster/vg01/dispersed_fuse/brick
>> Brick6: tethys:/gluster/vg01/dispersed_fuse/brick
>> Options Reconfigured:
>> client.event-threads: 16
>> server.event-threads: 16
>> performance.io-thread-count: 16
>> geo-replication.ignore-pid-check: on
>> geo-replication.indexing: on
>> features.quota: off
>> features.inode-quota: off
>> nfs.disable: on
>> storage.fips-mode-rchecksum: on
>> server.outstanding-rpc-limit: 512
>> server.root-squash: off
>> cluster.server-quorum-ratio: 51%
>> cluster.enable-shared-storage: enable
>>
>>
>> Any hints for root cause analysis are appreciated.
>>
>> Please let me know if you need more information.
>>
>>
>> Kind Regards,
>>
>> Felix
> Hi Felix,
>
> Usually for performance  issues  the devs need a  little bit more details.
>
> In your case you can :
> 1.  Test  with real workload  - as this  is what you are going to do with the Gluster. If that is not possible, you can run the synthetic benchmark focusing on the workload that is closest to the real one.
>
> 2. Check the groups of options in /var/lib/gluster/groups . There is a  'profile' group for DB,  Virtualization, small file workloads, etc . Play with those settings and adjust as necessary.
>
> 3. Obtain a gluster profile and use the 'top' command to gain more information about the pool's status.
> For details,  check https://docs.gluster.org/en/latest/Administrator%20Guide/Monitoring%20Workload/
>
> This information will allow more experienced adminiatrators and the developers to identify any pattern that could cause the symptoms.
>
> Tuning Gluster is one of the hardest topics,  so you should prepare yourself for a lot of test untill you reach the optimal settings for your volumes.
>
> Best Regards,
> Strahil Nikolov
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