From: Theodore Tso <tytso@mit.edu>
To: Greg Freemyer <greg.freemyer@gmail.com>
Cc: Ted Augustine <taugustine@techpathways.com>,
Alexey Fisher <bug-track@fisher-privat.net>,
linux-ext4@vger.kernel.org
Subject: Re: xt4 - True Readonly mount [WAS - Re: [Bug 14354] Bad corruption with 2.6.32-rc1 and upwards]
Date: Tue, 3 Nov 2009 08:52:42 -0500 [thread overview]
Message-ID: <20091103135242.GA6510@mit.edu> (raw)
In-Reply-To: <87f94c370911021359x19f57427o19e6f7bfcfadae21@mail.gmail.com>
On Mon, Nov 02, 2009 at 04:59:18PM -0500, Greg Freemyer wrote:
> Queisce application (databases, etc. have utils to do this.)
>
> Queisce filesystem (xfs_freeze -f can be done from userspace. is there
> a ext4 util?)
>
> issue raid array command to create snapshot.
>
> release filesystem (xfs_freeze -u)
>
> release the app (util provided by app).
>
> Mount the snapshot readonly (true readonly with zero writes to the
> block device).
>
> Backup the readonly snapshot (to tape, etc.).
This works today using ext4. The freeze ioctl quiesces the filesystem
and leaves the journal in clean state, so there is no need for a
journal replay. I take snapshots using LVM all the time. It's
slightly more work if you are using a hardware raid array since you
can't use a single integrated "lvcreate --snapshot" command, but
should Just Work today.
- Ted
prev parent reply other threads:[~2009-11-03 13:52 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-30 14:20 xt4 - True Readonly mount [WAS - Re: [Bug 14354] Bad corruption with 2.6.32-rc1 and upwards] Greg Freemyer
2009-10-30 15:14 ` Eric Sandeen
2009-10-30 15:31 ` Alexey Fisher
2009-10-30 16:14 ` Eric Sandeen
2009-10-30 16:52 ` Alexey Fisher
2009-10-30 17:13 ` Eric Sandeen
2009-10-30 17:43 ` Duane Griffin
2009-10-30 15:47 ` Alexey Fisher
2009-11-01 5:45 ` Theodore Tso
2009-11-02 21:59 ` Greg Freemyer
2009-11-02 22:53 ` Andreas Dilger
2009-11-02 23:02 ` Eric Sandeen
2009-11-04 8:05 ` Andreas Dilger
2009-11-04 16:20 ` Eric Sandeen
2009-11-03 13:52 ` Theodore Tso [this message]
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