[Gluster-users] Gluster distributed replicated setup does not serve read from all bricks belonging to the same replica

[Ravishankar N]

Hi,
If there are multiple clients , you can change the 
'cluster.read-hash-mode' volume option's value to 2. Then different 
reads should be served from different bricks for different clients. The 
meaning of various values for 'cluster.read-hash-mode' can be got from 
`gluster volume set help`. gluster-4.1 also has added a new value[1] to 
this option. Of course, the assumption is that all bricks host good 
copies (i.e. there are no self-heals pending).

Hope this helps,
Ravi

[1]  https://review.gluster.org/#/c/glusterfs/+/19698/

On 11/22/2018 10:20 AM, Anh Vo wrote:
> Hi,
> Our setup: We have a distributed replicated setup of 3 replica. The 
> total number of servers varies between clusters, in some cases we have 
> a total of 36 (12 x 3) servers, in some of them we have 12 servers (4 
> x 3). We're using gluster 3.12.15
>
> In all instances what I am noticing is that only one member of the 
> replica is serving read for a particular file, even when all the 
> members of the replica set is online. We have many large input files 
> (for example: 150GB zip file) and when there are 50 clients reading 
> from one single server the performance degrades by several magnitude 
> for reading that file only. Shouldn't all members of the replica 
> participate in serving the read requests?
>
> Our options
>
> cluster.shd-max-threads: 1
> cluster.heal-timeout: 900
> network.inode-lru-limit: 50000
> performance.md-cache-timeout: 600
> performance.cache-invalidation: on
> performance.stat-prefetch: on
> features.cache-invalidation-timeout: 600
> features.cache-invalidation: on
> cluster.metadata-self-heal: off
> cluster.entry-self-heal: off
> cluster.data-self-heal: off
> features.inode-quota: off
> features.quota: off
> transport.listen-backlog: 100
> transport.address-family: inet
> performance.readdir-ahead: on
> nfs.disable: on
> performance.strict-o-direct: on
> network.remote-dio: off
> server.allow-insecure: on
> performance.write-behind: off
> cluster.nufa: disable
> diagnostics.latency-measurement: on
> diagnostics.count-fop-hits: on
> cluster.ensure-durability: off
> cluster.self-heal-window-size: 32
> cluster.favorite-child-policy: mtime
> performance.io-thread-count: 32
> cluster.eager-lock: off
> server.outstanding-rpc-limit: 128
> cluster.rebal-throttle: aggressive
> server.event-threads: 3
> client.event-threads: 3
> performance.cache-size: 6GB
> cluster.readdir-optimize: on
> storage.build-pgfid: on
>
>
>
>
>
>
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