[ovirt-users] Very poor GlusterFS performance

Sat Jul 8 07:34:54 UTC 2017

So ovirt access gluster vai FUSE ? i thought its using libgfapi.

When can we expect it to work with libgfapi ?

and what about the changelog of 4.1.3 ?

BZ 1022961 Gluster: running a VM from a gluster domain should use gluster URI instead of a fuse mount"

--

Respectfully
Mahdi A. Mahdi

________________________________
From: users-bounces at ovirt.org <users-bounces at ovirt.org> on behalf of Ralf Schenk <rs at databay.de>
Sent: Monday, June 19, 2017 7:32:45 PM
To: users at ovirt.org
Subject: Re: [ovirt-users] Very poor GlusterFS performance

Hello,

Gluster-Performance is bad. Thats why I asked for native qemu-libgfapi access for Ovirt-VM's to gluster volumes which I thought to be possible since 3.6.x. Documentation is misleading and still in 4.1.2 Ovirt is using fuse to mount gluster-based VM-Disks.

Bye

Am 19.06.2017 um 17:23 schrieb Darrell Budic:
Chris-

You probably need to head over to gluster-users at gluster.org<mailto:gluster-users at gluster.org> for help with performance issues.

That said, what kind of performance are you getting, via some form or testing like bonnie++ or even dd runs? Raw bricks vs gluster performance is useful to determine what kind of performance you’re actually getting.

Beyond that, I’d recommend dropping the arbiter bricks and re-adding them as full replicas, they can’t serve distributed data in this configuration and may be slowing things down on you. If you’ve got a storage network setup, make sure it’s using the largest MTU it can, and consider adding/testing these settings that I use on my main storage volume:

performance.io<http://performance.io>-thread-count: 32
client.event-threads: 8
server.event-threads: 3
performance.stat-prefetch: on

Good luck,

  -Darrell

On Jun 19, 2017, at 9:46 AM, Chris Boot <bootc at bootc.net<mailto:bootc at bootc.net>> wrote:

Hi folks,

I have 3x servers in a "hyper-converged" oVirt 4.1.2 + GlusterFS 3.10
configuration. My VMs run off a replica 3 arbiter 1 volume comprised of
6 bricks, which themselves live on two SSDs in each of the servers (one
brick per SSD). The bricks are XFS on LVM thin volumes straight onto the
SSDs. Connectivity is 10G Ethernet.

Performance within the VMs is pretty terrible. I experience very low
throughput and random IO is really bad: it feels like a latency issue.
On my oVirt nodes the SSDs are not generally very busy. The 10G network
seems to run without errors (iperf3 gives bandwidth measurements of >=
9.20 Gbits/sec between the three servers).

To put this into perspective: I was getting better behaviour from NFS4
on a gigabit connection than I am with GlusterFS on 10G: that doesn't
feel right at all.

My volume configuration looks like this:

Volume Name: vmssd
Type: Distributed-Replicate
Volume ID: d5a5ddd1-a140-4e0d-b514-701cfe464853
Status: Started
Snapshot Count: 0
Number of Bricks: 2 x (2 + 1) = 6
Transport-type: tcp
Bricks:
Brick1: ovirt3:/gluster/ssd0_vmssd/brick
Brick2: ovirt1:/gluster/ssd0_vmssd/brick
Brick3: ovirt2:/gluster/ssd0_vmssd/brick (arbiter)
Brick4: ovirt3:/gluster/ssd1_vmssd/brick
Brick5: ovirt1:/gluster/ssd1_vmssd/brick
Brick6: ovirt2:/gluster/ssd1_vmssd/brick (arbiter)
Options Reconfigured:
nfs.disable: on
transport.address-family: inet6
performance.quick-read: off
performance.read-ahead: off
performance.io<http://performance.io>-cache: off
performance.stat-prefetch: off
performance.low-prio-threads: 32
network.remote-dio: off
cluster.eager-lock: enable
cluster.quorum-type: auto
cluster.server-quorum-type: server
cluster.data-self-heal-algorithm: full
cluster.locking-scheme: granular
cluster.shd-max-threads: 8
cluster.shd-wait-qlength: 10000
features.shard: on
user.cifs: off
storage.owner-uid: 36
storage.owner-gid: 36
features.shard-block-size: 128MB
performance.strict-o-direct: on
network.ping-timeout: 30
cluster.granular-entry-heal: enable

I would really appreciate some guidance on this to try to improve things
because at this rate I will need to reconsider using GlusterFS altogether.

Cheers,
Chris

--
Chris Boot
bootc at bootc.net<mailto:bootc at bootc.net>
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Ralf Schenk
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