[Gluster-users] VM crash, store in glusterfs

[SATHEESARAN]

On 07/02/2015 03:32 PM, Gregor Burck wrote:
> Hi,
>
> I would like to ade some test with glusterfs and virtualbox.
> The goal is to store the virtualbox files in a glusterfs store and 
> access it from to machines.
>
> In my setup, the servers are the clients too. I hope you could 
> understand my description:
>
> I remount the share back to the single machines
>
>
> two machines:
> gf001 and gf002
>
> Both:
> debian 8
> glusterfs 3.7
>
> /dev/sda - root
> /dev/sdb - /export/vbstore
>
> My volume info:
> root at gf001  :~# gluster volume info vbstore
>
> Volume Name: vbstore
> Type: Replicate
> Volume ID: 7bf8aa42-8fd9-4535-888d-dacea4f14a83
> Status: Started
> Number of Bricks: 1 x 2 = 2
> Transport-type: tcp
> Bricks:
> Brick1: gf001.mvz.ffm:/export/vbstore
> Brick2: gf002.mvz.ffm:/export/vbstore
> Options Reconfigured:
> cluster.server-quorum-type: server
> cluster.quorum-type: auto
> network.remote-dio: enable
> cluster.eager-lock: enable
> performance.stat-prefetch: off
> performance.io-cache: off
> performance.read-ahead: off
> performance.quick-read: off
> performance.readdir-ahead: on
>
>
> mounting on gf001:
> mount -t glusterfs gf001:/vbstore /import/vbstore
> or via fstab:
> gf001:/vbstore        /import/vbstore glusterfs defaults 0 0
>
> The same on gf002 with gf002 as server.
>
> Creating an virtualbox VM in /import/vbstore.
>
> Starting VM on gf001 OR gf002 work right.
>
> But when running VM on one AND shut down the opposit, the VM crash 
> with ATA failure.
>
>
> Maybe mount or gluster setting options?
>
> Thank you for help,
>
> Gregor
>
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Hi Gregor,

Volume info shows that server-side quorum and client-side quorum are 
enabled.

If there are only 2 nodes ( gf001 & gf002 ) are there in the cluster, then
server-side quorum is not met, which would result in killing bricks of 
the volumes.
You can check this from 'gluster volume status <vol-name>'

Also client-side quorum has a limitation with replica 2 volume, that the 
first brick of the replicate
should always be up. In your case, if you shutdown gf001, then the 
client-side quorum will not be met and
that would result in gluster volume becoming read-only

Under these situation, VM should not crash, but will go paused as the 
storage is inaccessible ( read-only in the case of client quorum not met )

Hope that helps.

Thanks,
Satheesaran S