[Gluster-users] Gluster Performance Issues

[Strahil Nikolov]

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