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From: Kevin Corry <kevcorry@us.ibm.com>
To: linux-kernel@vger.kernel.org
Cc: "roland" <devzero@web.de>
Subject: Re: is there a COW inside the kernel ?
Date: Fri, 3 Mar 2006 16:39:58 -0600	[thread overview]
Message-ID: <200603031639.58616.kevcorry@us.ibm.com> (raw)
In-Reply-To: <04cd01c63f09$a007a930$0200000a@aldipc>

On Fri March 3 2006 3:29 pm, roland wrote:
> i think i will take a closer look on device-mapper, but i'm unsure if it`s
> perfectly suited.
>
> can i only use devices, not files for the cow?

Yes, Device-Mapper can only map to block-devices. If you need to do this with 
files, you could use losetup to create block-device from them. However, the 
COW device still won't "grow" automatically as you described.

> what about merging a cow-dev/file back to the r/o-dev/file ?

Device-Mapper does not directly support this, but EVMS provides a "rollback" 
function for reverting an origin volume back to the contents of its snapshot 
volume.

-- 
Kevin Corry
kevcorry@us.ibm.com
http://www.ibm.com/linux/
http://evms.sourceforge.net/

  reply	other threads:[~2006-03-03 22:34 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-03-03  8:29 is there a COW inside the kernel ? roland
2006-03-03 13:33 ` Jan Engelhardt
2006-03-03 14:19 ` Alasdair G Kergon
2006-03-03 14:28 ` Kevin Corry
2006-03-03 21:29   ` roland
2006-03-03 22:39     ` Kevin Corry [this message]
2006-03-04  5:35     ` Jon Masters
2006-03-03 15:25 ` Jeff Dike

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