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From: NeilBrown <neilb@suse.de>
To: Piergiorgio Sartor <piergiorgio.sartor@nexgo.de>
Cc: linux-raid@vger.kernel.org
Subject: Re: Superblock backup
Date: Fri, 11 May 2012 08:50:57 +1000	[thread overview]
Message-ID: <20120511085057.27790c1a@notabene.brown> (raw)
In-Reply-To: <20120510174431.GA3019@lazy.lzy>

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On Thu, 10 May 2012 19:44:31 +0200 Piergiorgio Sartor
<piergiorgio.sartor@nexgo.de> wrote:

> Hi,
> 
> again, following the RAID-5 story, I was wondering
> if could make sense to have a new superblock type,
> let's say 2.x, having backup copies (of persistent
> or quasi persistent data) in different areas of the
> drive components.
> This would be similar to filesystem or gpt.
> 
> Is there anything planned for this?

This is one of the idea that has floated around in my head for a while,
possibly a v1.3 metadata.

However my thought there was always to protect against a bad block on the
device.  Protecting against data corruption due to bugs or sys-admin mistakes
is always best handled by backups.
e.g. take a 'dump' (either binary or textual) of the metadata every day, or
every reboot or something. (And store it on a different host).

Both are probably useful, but for the recently problem, a regular backup
would be the most useful.

> 
> In any case, it would be still interesting to have
> a "backup" capability at hand, like a "dd" of the
> superblock to some secure file.

"mdadm -E" would probably be enough - just write a cron job :-)

NeilBrown


> 
> Any idea or suggestions?
> 
> Thanks,
> 
> bye,
> 


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  reply	other threads:[~2012-05-10 22:50 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-05-10 17:44 Superblock backup Piergiorgio Sartor
2012-05-10 22:50 ` NeilBrown [this message]
2012-05-11 18:15   ` Piergiorgio Sartor

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