[Gluster-users] VM crash, store in glusterfs

[SATHEESARAN]

On 07/04/2015 08:41 AM, SATHEESARAN wrote:
> 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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>> Gluster-users at gluster.org
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> Hi Gregor,
>
> Volume info shows that server-side quorum and client-side quorum are 
> enabled.
>
Missed a clear description here - When you shutdown one of the node in a 
2 node cluster with quorums enabled,
you will face the following situation.
> 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
>
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