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Date: Tue, 7 Jan 2003 11:53:57 -0700
From: Andreas Dilger <adilger@clusterfs.com>
To: John Bradford <john@grabjohn.com>
Cc: root@chaos.analogic.com, maxvaldez@yahoo.com, bulb@ucw.cz,
       linux-kernel@vger.kernel.org
Subject: Re: Virtual WORM device
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References: <Pine.LNX.3.95.1030107131613.3523A-100000@chaos.analogic.com> <200301071841.h07If7QJ002323@darkstar.example.net>
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In-Reply-To: <200301071841.h07If7QJ002323@darkstar.example.net>; from john@grabjohn.com on Tue, Jan 07, 2003 at 06:41:07PM +0000
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On Jan 07, 2003  18:41 +0000, John Bradford wrote:
> > Somebody should then modify `rm` and the kernel unlink
> > to `mv' files to the dumpster directory on the
> > file-system, instead of really deleting them.
> 
> Another possibility would be to create a meta-device that works like a
> cross between the loopback device, and WORM device, I.E. start at the
> begining, and allocate sectors sequentially.  Whenever a sector would
> normally be overwritten, a new one is allocated instead.  This way,
> you could always access the filesystem as it was at any mount in time.

This is commonly called a filesystem snapshot, and you can already do
it with LVM.

Cheers, Andreas
--
Andreas Dilger
http://sourceforge.net/projects/ext2resize/
http://www-mddsp.enel.ucalgary.ca/People/adilger/

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