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From: Michael Locher <locher@iam.unibe.ch>
Subject: Re: Is xfsdump operation atomic?
Date: Wed, 24 Nov 2004 09:50:56 +0100
To: linux-xfs@oss.sgi.com
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Ivan, thanks for commenting on this.

Am 23.11.2004 um 13:12 schrieb  Ivan Rayner:
> You seem to be of the opinion that you can't create a backup of a live
> filesystem.  My guess is that you assume a backup is a strict snapshot 
> in
> time of the filesystem -- it isn't.

But it could be... it would be a nice feature to have, tough i am sure 
it is not trivial to implement.

> If a file is removed or created while a xfsdump is running, then it 
> may or
> may not be included in the dump.  This is OK, because in tomorrow 
> night's
> incremental backup the file will then be included or removed as
> appropriate.  If you have a 24hr schedule then you should assume that 
> the
> cycle starts when xfsdump starts.  Anything that happens while xfsdump 
> is
> running will be guaranteed to be on the following dump, but if you're
> lucky then it will make it in the current dump.

What happens if a large file (eg a multi GB database file) is modified 
during the dump.
Will it be consistent? i.e are write operations allowed on a file when 
its data is dumped?

Michael