[Users] which file system for shared disk?

Piotr Szubiakowski piotr.szubiakowski at nask.pl
Thu Jul 11 10:45:41 UTC 2013



> On 07/11/2013 12:52 PM, Piotr Szubiakowski wrote:
>>
>>>> The way that oVirt manage storage domains accessed via FC is very 
>>>> smart.
>>>> There is separate logical volume for each virtual disk. But I think 
>>>> that
>>>> logical volume at the same time could be "touched" only by one 
>>>> host. Is
>>>> it possible that two host access read/write the same logical volume 
>>>> and
>>>> there is no data corruption?
>>>
>>> hence a shared disk over block storage using LVM must be 
>>> pre-allocated, so no LV changes (lv extend) would be needed.
>>> (also, it cannot have snapshots, since it would become qcow)
>>
>> Ok, but this is the hypervisor view. For a guest OS this LV is normal 
>> RAW block device. I wonder if someone test this feature and access 
>> shared disk from many VM's at the same time?
> I did a brief tests - 3 vms, shared disk, cman/pacemaker + gfs2 - had 
> no problems using it, no data corruption. although that was only basic 
> tests, like create/move/delete files, no extensive usage/stress or 
> something like that.

Thanks Yuri,
Is fencing handled by the cman/pacemaker? I read about the fanced daemon 
and it seems to be difficult to use it together with oVirt.

Piotr



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