From: Phil Turmel <philip@turmel.org>
To: tbayly@bluehost.com
Cc: linux-raid <linux-raid@vger.kernel.org>
Subject: Re: Specifying a data offset?
Date: Wed, 08 May 2013 16:44:20 -0400 [thread overview]
Message-ID: <518AB924.2010002@turmel.org> (raw)
In-Reply-To: <1368044274.3368.364.camel@148>
On 05/08/2013 04:17 PM, Tregaron Bayly wrote:
> We have lots of mirrors all over our network and over time this means
> arrays created by different versions of mdadm. In turn this means that
> we have all sorts of data offsets, including a 2.3.5 mdadm version that
> offset the data 262,144 sectors. I can't fathom why I need my data to
> start 128M from the beginning of the disk, but whatever.
>
> Inevitably an admin decided that doing a --create over the top of an
> existing array was a good and necessary thing and when finished we
> couldn't find the filesystem. Bringing it back online was simply a case
> of finding the correct offset, locating an mdadm version that would
> specify it properly and doing another create. Through the whole
> exercise I found myself wondering why there isn't a command line
> argument to specify the data offset if something other than the default
> is desired. I think that implementing the argument and reading the
> value in init_super wouldn't be terribly difficult so I must be missing
> an obvious reason. Can someone explain to me why this feature isn't
> desirable?
This desirable and has been implemented. Check out the development
version of mdadm and look at the "--data-offset" option.
It does not exist in a released version yet, but it has been cooking
since October.
Phil
next prev parent reply other threads:[~2013-05-08 20:44 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-08 20:17 Specifying a data offset? Tregaron Bayly
2013-05-08 20:44 ` Phil Turmel [this message]
2013-05-08 23:03 ` Tregaron Bayly
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