From: Asdo <asdo@shiftmail.org>
To: Amir Goldstein <amir73il@gmail.com>
Cc: linux-ext4@vger.kernel.org
Subject: Re: Filesystem freeze vs blockdevice snapshot
Date: Mon, 16 Jan 2012 18:03:07 +0100 [thread overview]
Message-ID: <4F14584B.9080008@shiftmail.org> (raw)
In-Reply-To: <CAOQ4uxhTueTHi3UP3AdQo1x1+ONx4Fn8t1F_s9PLZu6arhzN7Q@mail.gmail.com>
[sorry for double posting : had forgot to remove html]
Thanks but it's still not clear to me.
What do you mean with "clean fs"? is that in any way different from an
image after a sudden power loss?
Secondarily, how can LVM know what filesystem is underneath and call the
proper freeze? That's a bare block device, there might not even be a
filesystem under LVM; or it might be exported via iSCSI to an XYZ
operating system using the Xyzfs filesystem which Linux knows nothing
about...
Thank you
On 01/14/12 19:33, Amir Goldstein wrote:
> LVM2 already does the fs freeze for you before taking the snapshot.
> it's the only way to get a block device snapshot of a "clean" fs.
> hope that answers your question.
>
> On Fri, Jan 13, 2012 at 5:30 PM, Asdo <asdo@shiftmail.org
> <mailto:asdo@shiftmail.org>> wrote:
>
> Hello all,
> please excuse the silly question...
>
> What is the benefit of performing an ext4 fs freeze before taking
> a snapshot of the underlying block device with LVM2 ?
>
> Is the freeze step useful or I can go with the snapshot directly?
>
> And/or is there another use case for the freeze?
>
> Thank you
> --
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>
next prev parent reply other threads:[~2012-01-16 17:03 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-13 15:30 Filesystem freeze vs blockdevice snapshot Asdo
[not found] ` <CAOQ4uxhTueTHi3UP3AdQo1x1+ONx4Fn8t1F_s9PLZu6arhzN7Q@mail.gmail.com>
2012-01-16 17:03 ` Asdo [this message]
2012-01-16 19:16 ` Jan Kara
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