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Date: Thu, 24 Feb 2011 13:25:16 -0600
From: Les Mikesell <lesmikesell@gmail.com>
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Subject: Re: [linux-lvm] Snapshots and disk re-use
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To: linux-lvm@redhat.com

On 2/24/2011 1:15 PM, Nataraj wrote:
>
> One other thing that wasn't mentioned here.... As far as I understand,
> if these are lvms on the host and the snapshots are being taken on the
> host, there is no guaranteed integrity of the filesystems unless you
> shutdown the guest while the snapshot is taken.
>
> It's too bad they don't implement a system call that could do something
> like sync filesystem and sleep until I tell you to continue.  This would
> be perfect for snapshot backups of virtual hosts.

Syncing a filesystem's OS buffers isn't really enough to ensure that 
running apps have saved their data in a consistent state.  The best you 
are going to get without shuting things down is more or less what you'd 
have if the server crashed at some point in time.

-- 
   Les Mikesell
    lesmikesell@gmail.com