[Gluster-users] GlusterFS as virtual machine storage

[Alastair Neil]

you need to set

cluster.server-quorum-ratio             51%

On 6 September 2017 at 10:12, Pavel Szalbot <pavel.szalbot at gmail.com> wrote:

> Hi all,
>
> I have promised to do some testing and I finally find some time and
> infrastructure.
>
> So I have 3 servers with Gluster 3.10.5 on CentOS 7. I created
> replicated volume with arbiter (2+1) and VM on KVM (via Openstack)
> with disk accessible through gfapi. Volume group is set to virt
> (gluster volume set gv_openstack_1 virt). VM runs current (all
> packages updated) Ubuntu Xenial.
>
> I set up following fio job:
>
> [job1]
> ioengine=libaio
> size=1g
> loops=16
> bs=512k
> direct=1
> filename=/tmp/fio.data2
>
> When I run fio fio.job and reboot one of the data nodes, IO statistics
> reported by fio drop to 0KB/0KB and 0 IOPS. After a while, root
> filesystem gets remounted as read-only.
>
> If you care about infrastructure, setup details etc., do not hesitate to
> ask.
>
> Gluster info on volume:
>
> Volume Name: gv_openstack_1
> Type: Replicate
> Volume ID: 2425ae63-3765-4b5e-915b-e132e0d3fff1
> Status: Started
> Snapshot Count: 0
> Number of Bricks: 1 x (2 + 1) = 3
> Transport-type: tcp
> Bricks:
> Brick1: gfs-2.san:/export/gfs/gv_1
> Brick2: gfs-3.san:/export/gfs/gv_1
> Brick3: docker3.san:/export/gfs/gv_1 (arbiter)
> Options Reconfigured:
> nfs.disable: on
> transport.address-family: inet
> performance.quick-read: off
> performance.read-ahead: off
> performance.io-cache: off
> performance.stat-prefetch: off
> performance.low-prio-threads: 32
> network.remote-dio: enable
> 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
>
> Partial KVM XML dump:
>
>     <disk type='network' device='disk'>
>       <driver name='qemu' type='raw' cache='none'/>
>       <source protocol='gluster'
> name='gv_openstack_1/volume-77ebfd13-6a92-4f38-b036-e9e55d752e1e'>
>         <host name='10.0.1.201' port='24007'/>
>       </source>
>       <backingStore/>
>       <target dev='vda' bus='virtio'/>
>       <serial>77ebfd13-6a92-4f38-b036-e9e55d752e1e</serial>
>       <alias name='virtio-disk0'/>
>       <address type='pci' domain='0x0000' bus='0x00' slot='0x04'
> function='0x0'/>
>     </disk>
>
> Networking is LACP on data nodes, stack of Juniper EX4550's (10Gbps
> SFP+), separate VLAN for Gluster traffic, SSD only on Gluster all
> nodes (including arbiter).
>
> I would really love to know what am I doing wrong, because this is my
> experience with Gluster for a long time a and a reason I would not
> recommend it as VM storage backend in production environment where you
> cannot start/stop VMs on your own (e.g. providing private clouds for
> customers).
> -ps
>
>
> On Sun, Sep 3, 2017 at 10:21 PM, Gionatan Danti <g.danti at assyoma.it>
> wrote:
> > Il 30-08-2017 17:07 Ivan Rossi ha scritto:
> >>
> >> There has ben a bug associated to sharding that led to VM corruption
> >> that has been around for a long time (difficult to reproduce I
> >> understood). I have not seen reports on that for some time after the
> >> last fix, so hopefully now VM hosting is stable.
> >
> >
> > Mmmm... this is precisely the kind of bug that scares me... data
> corruption
> > :|
> > Any more information on what causes it and how to resolve? Even if in
> newer
> > Gluster releases it is a solved bug, knowledge on how to treat it would
> be
> > valuable.
> >
> >
> > Thanks.
> >
> > --
> > Danti Gionatan
> > Supporto Tecnico
> > Assyoma S.r.l. - www.assyoma.it
> > email: g.danti at assyoma.it - info at assyoma.it
> > GPG public key ID: FF5F32A8
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> > Gluster-users at gluster.org
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