[Linux-cluster] Snapshotting GFS and freezing
Dirk H. Schulz
dirk.schulz at kinzesberg.de
Sat Jan 23 10:12:54 UTC 2010
Ray Van Dolson schrieb:
> On Wed, Jan 20, 2010 at 06:14:02AM -0800, Dirk H. Schulz wrote:
>
>> That means calling
>> sync
>> echo 3 > /proc/sys/vm/drop_caches
>> inside the VM, right? Or is there anything more to do to flush everything?
>>
>> Dirk
>>
>
> I would think the best way would be to actually pause the VM. If you
> snapshot a VM while it's running, even with the above, how can you
> guarantee an application won't do something on the VM right as the
> snapshot occurs?
>
That is an important point, I am already pondering about it. Of course
pausing the vm is the better option - if you can afford it.
I am working systematically on an environment where the possibility of
very high level availability vms is part of the design (e.g. 99,99 %).
At the moment the only approach I can see is doing snapshots of a
running vm and making those as reliable as possible.
Dirk
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