From: "Rechenberg, Andrew" <ARechenberg@shermanfinancialgroup.com>
To: AndyLiebman@aol.com
Cc: linux-raid@vger.kernel.org
Subject: Re: RAID 10 and Persistent Superblock
Date: Fri, 31 Oct 2003 12:33:59 -0500 [thread overview]
Message-ID: <1067621639.6601.5.camel@localhost.localdomain> (raw)
In-Reply-To: <c6.2446066e.2cd3d85c@aol.com>
I have a 56-disk RAID10 and I have persistent superblocks on all of the
md devices. I believe the RAID code is smart enough to know that a
superblock already exists and places a new superblock 'before' the other
one.
So the end of your disk should look like the following drawing:
-----------------------------------|
DATA | RAID0SB | RAID1SB |
-----------------------------------|
When I created my RAID10 array, I believe that the superblocks were
created in this fashion. Any RAID guru care to comment?
Regards,
Andy.
On Fri, 2003-10-31 at 10:23, AndyLiebman@aol.com wrote:
> A "simple" question regarding RAID 10. When I make a RAID 0 on top of three
> RAID 1 arrays, should I use "persistent superblock = 1" in that top level
> array? Won't that confuse the RAID software by putting two different UUIDs on the
> drives -- one for the RAID 1 arrays and one for the RAID 0 array?
>
> As long as I have UUIDs for the three lower level RAID 1 arrays, I should be
> able to start those arrays with mdadm even if my device ids change.
>
> Then shouldn't I be able to start the top level array without a UUID -- just
> by referring to the mdX numbers? In other words, if md0, md1, md2 start, there
> shouldn't be any confusion about which are the correct devices to start up
> md3. Or am I missing something?
>
> Appreciate your answers.
>
> Andy Liebman
> -
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--
Regards,
Andrew Rechenberg
Infrastructure Team, Sherman Financial Group
prev parent reply other threads:[~2003-10-31 17:33 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-10-31 15:23 RAID 10 and Persistent Superblock AndyLiebman
2003-10-31 17:33 ` Rechenberg, Andrew [this message]
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