Re: [Xen-users] does live migration require a cluster aware filesystem?

["Fajar A. Nugraha" <fajar@xxxxxxxxxxxxx>]

Tomoki Taniguchi wrote:
> On Nov 6, 2007 4:41 PM, Fajar A. Nugraha <fajar@xxxxxxxxxxxxx> wrote:
>   
>> Tomoki Taniguchi wrote:
>>     
>>> I can't seem to get find a straight answer to this question,
>>> so i decided to ask it directly.
>>>
>>> If i want to do a live migration between two xen servers which has the 
>>> domainU
>>> filesystem shared to them using nbd, does the filesystem have to be
>>> cluster aware like
>>> gfs?  or can it be ext3 since technically the two servers should never
>>> be writing to
>>> the filesystem at the same time?
>>>
>>>       
>> If you store domU disks as files on dom0, then yes, you need a cluster
>> file system.
>> If you store domU disks as LVM (or other block device) on dom0, then no.
>> Both dom0 involved in migration simply need to have access to the same
>> block device. For example, you can have a server exporting LVs via
>> iscsi, and several dom0's using them as domU storage.
>>     
>
> thank you.  can i assume this applies to nbd shared devices as well?
>
>   
Yes.
>>> I was thinking since windows servers with ntfs filesystems doesn't
>>> seem to have a problem,
>>>
>>>       
>> Really? Are you saying that two windows servers can mount the same
>> ntfs-formatted block device at the SAME TIME without a problem?
>>     
>
> no what i mean is that it is possible to do a live migration of windows
> domUs. and as far as i know NTFS is not cluster-aware.  so it stands
> to reason that ext3 should be able to with stand a live migration as well.
>
>   

Perhaps I misunderstood your question.
If you store your domU storage as files on dom0, then dom0 filesystem
needs to be cluster aware for live migration to work.

However, no such requirement apply for domU. So if your domU is just a
normal, non-cluster server, then ext3 will work just fine on domU.

Regards,

Fajar

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