----- Original Message ----- > From: "Abi Askushi" <rightkicktech@xxxxxxxxx> > To: "Krutika Dhananjay" <kdhananj@xxxxxxxxxx> > Cc: "gluster-user" <gluster-users@xxxxxxxxxxx> > Sent: Tuesday, September 5, 2017 5:02:46 AM > Subject: Re: Slow performance of gluster volume > > Hi Krutika, > > I already have a preallocated disk on VM. > Now I am checking performance with dd on the hypervisors which have the > gluster volume configured. > > I tried also several values of shard-block-size and I keep getting the same > low values on write performance. > Enabling client-io-threads also did not have any affect. > > The version of gluster I am using is glusterfs 3.8.12 built on May 11 2017 > 18:46:20. > The setup is a set of 3 Centos 7.3 servers and ovirt 4.1, using gluster as > storage. > > Below are the current settings: > > > Volume Name: vms > Type: Replicate > Volume ID: 4513340d-7919-498b-bfe0-d836b5cea40b > Status: Started > Snapshot Count: 0 > Number of Bricks: 1 x (2 + 1) = 3 > Transport-type: tcp > Bricks: > Brick1: gluster0:/gluster/vms/brick > Brick2: gluster1:/gluster/vms/brick > Brick3: gluster2:/gluster/vms/brick (arbiter) > Options Reconfigured: > server.event-threads: 4 > client.event-threads: 4 > performance.client-io-threads: on > features.shard-block-size: 512MB > cluster.granular-entry-heal: enable > performance.strict-o-direct: on > network.ping-timeout: 30 > storage.owner-gid: 36 > storage.owner-uid: 36 > user.cifs: off > features.shard: on > cluster.shd-wait-qlength: 10000 > cluster.shd-max-threads: 8 > cluster.locking-scheme: granular > cluster.data-self-heal-algorithm: full > cluster.server-quorum-type: server > cluster.quorum-type: auto > cluster.eager-lock: enable > network.remote-dio: off > performance.low-prio-threads: 32 > performance.stat-prefetch: on > performance.io-cache: off > performance.read-ahead: off > performance.quick-read: off > transport.address-family: inet > performance.readdir-ahead: on > nfs.disable: on > nfs.export-volumes: on > > > I observed that when testing with dd if=/dev/zero of=testfile bs=1G count=1 I > get 65MB/s on the vms gluster volume (and the network traffic between the > servers reaches ~ 500Mbps), while when testing with dd if=/dev/zero > of=testfile bs=1G count=1 oflag=direct I get a consistent 10MB/s and the > network traffic hardly reaching 100Mbps. I have a replica 3 volume that I was seeing ~65 MB / sec on my VMs, I ended up upgrading to a newer version and now I get closer to 150-180 MB / sec writes. Since you are using arbiter I would expect faster writes for you, what gluster version are you running? What OS? -b > > Any other things one can do? > > On Tue, Sep 5, 2017 at 5:57 AM, Krutika Dhananjay < kdhananj@xxxxxxxxxx > > wrote: > > > > I'm assuming you are using this volume to store vm images, because I see > shard in the options list. > > Speaking from shard translator's POV, one thing you can do to improve > performance is to use preallocated images. > This will at least eliminate the need for shard to perform multiple steps as > part of the writes - such as creating the shard and then writing to it and > then updating the aggregated file size - all of which require one network > call each, which further get blown up once they reach AFR (replicate) into > many more network calls. > > Second, I'm assuming you're using the default shard block size of 4MB (you > can confirm this using `gluster volume get <VOL> shard-block-size`). In our > tests, we've found that larger shard sizes perform better. So maybe change > the shard-block-size to 64MB (`gluster volume set <VOL> shard-block-size > 64MB`). > > Third, keep stat-prefetch enabled. We've found that qemu sends quite a lot of > [f]stats which can be served from the (md)cache to improve performance. So > enable that. > > Also, could you also enable client-io-threads and see if that improves > performance? > > Which version of gluster are you using BTW? > > -Krutika > > > On Tue, Sep 5, 2017 at 4:32 AM, Abi Askushi < rightkicktech@xxxxxxxxx > > wrote: > > > > Hi all, > > I have a gluster volume used to host several VMs (managed through oVirt). > The volume is a replica 3 with arbiter and the 3 servers use 1 Gbit network > for the storage. > > When testing with dd (dd if=/dev/zero of=testfile bs=1G count=1 oflag=direct) > out of the volume (e.g. writing at /root/) the performance of the dd is > reported to be ~ 700MB/s, which is quite decent. When testing the dd on the > gluster volume I get ~ 43 MB/s which way lower from the previous. When > testing with dd the gluster volume, the network traffic was not exceeding > 450 Mbps on the network interface. I would expect to reach near 900 Mbps > considering that there is 1 Gbit of bandwidth available. This results having > VMs with very slow performance (especially on their write operations). > > The full details of the volume are below. Any advise on what can be tweaked > will be highly appreciated. > > Volume Name: vms > Type: Replicate > Volume ID: 4513340d-7919-498b-bfe0-d836b5cea40b > Status: Started > Snapshot Count: 0 > Number of Bricks: 1 x (2 + 1) = 3 > Transport-type: tcp > Bricks: > Brick1: gluster0:/gluster/vms/brick > Brick2: gluster1:/gluster/vms/brick > Brick3: gluster2:/gluster/vms/brick (arbiter) > Options Reconfigured: > cluster.granular-entry-heal: enable > performance.strict-o-direct: on > network.ping-timeout: 30 > storage.owner-gid: 36 > storage.owner-uid: 36 > user.cifs: off > features.shard: on > cluster.shd-wait-qlength: 10000 > cluster.shd-max-threads: 8 > cluster.locking-scheme: granular > cluster.data-self-heal-algorithm: full > cluster.server-quorum-type: server > cluster.quorum-type: auto > cluster.eager-lock: enable > network.remote-dio: off > performance.low-prio-threads: 32 > performance.stat-prefetch: off > performance.io-cache: off > performance.read-ahead: off > performance.quick-read: off > transport.address-family: inet > performance.readdir-ahead: on > nfs.disable: on > nfs.export-volumes: on > > > Thanx, > Alex > > _______________________________________________ > Gluster-users mailing list > Gluster-users@xxxxxxxxxxx > http://lists.gluster.org/mailman/listinfo/gluster-users > > > > _______________________________________________ > Gluster-users mailing list > Gluster-users@xxxxxxxxxxx > http://lists.gluster.org/mailman/listinfo/gluster-users _______________________________________________ Gluster-users mailing list Gluster-users@xxxxxxxxxxx http://lists.gluster.org/mailman/listinfo/gluster-users
