From: "Justin T. Gibbs" <gibbs@scsiguy.com>
To: Jeff Garzik <jgarzik@pobox.com>
Cc: linux-kernel@vger.kernel.org, Kevin Corry <kevcorry@us.ibm.com>,
Neil Brown <neilb@cse.unsw.edu.au>,
linux-raid@vger.kernel.org
Subject: Re: "Enhanced" MD code avaible for review
Date: Thu, 25 Mar 2004 17:10:24 -0700 [thread overview]
Message-ID: <1048370000.1080259823@aslan.btc.adaptec.com> (raw)
In-Reply-To: <406372C5.600@pobox.com>
>> None of the solutions being talked about perform "failing over" in
>> userland. The RAID transforms which perform this operation are kernel
>> resident in DM, MD, and EMD. Perhaps you are talking about spare
>> activation and rebuild?
>
> This is precisely why I sent the second email, and made the qualification
> I did :)
>
> For a "do it in userland" solution, an initrd or initramfs piece examines
> the system configuration, and assembles physical disks into RAID arrays
> based on the information it finds. I was mainly implying that an initrd
> solution would have to provide some primitive failover initially, before
> the kernel is bootstrapped... much like a bootloader that supports booting
> off a RAID1 array would need to do.
"Failover" (i.e. redirecting a read to a viable member) will not occur
via userland at all. The initrd solution just has to present all available
members to the kernel interface performing the RAID transform. There
is no need for "special failover handling" during bootstrap in either
case.
--
Justin
next prev parent reply other threads:[~2004-03-26 0:10 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-03-19 20:19 "Enhanced" MD code avaible for review Justin T. Gibbs
2004-03-23 5:05 ` Neil Brown
2004-03-23 6:23 ` Justin T. Gibbs
2004-03-24 2:26 ` Neil Brown
2004-03-24 19:09 ` Matt Domsch
2004-03-25 2:21 ` Jeff Garzik
2004-03-25 18:00 ` Kevin Corry
2004-03-25 18:42 ` Jeff Garzik
2004-03-25 18:48 ` Jeff Garzik
2004-03-25 23:46 ` Justin T. Gibbs
2004-03-26 0:01 ` Jeff Garzik
2004-03-26 0:10 ` Justin T. Gibbs [this message]
2004-03-26 0:14 ` Jeff Garzik
2004-03-25 22:04 ` Lars Marowsky-Bree
2004-03-26 19:19 ` Kevin Corry
2004-03-31 17:07 ` Randy.Dunlap
2004-03-25 23:35 ` Justin T. Gibbs
2004-03-26 0:13 ` Jeff Garzik
2004-03-26 17:43 ` Justin T. Gibbs
2004-03-28 0:06 ` Lincoln Dale
2004-03-30 17:54 ` Justin T. Gibbs
2004-03-28 0:30 ` Jeff Garzik
2004-03-26 19:15 ` Kevin Corry
2004-03-26 20:45 ` Justin T. Gibbs
2004-03-27 15:39 ` Kevin Corry
2004-03-28 9:11 ` [dm-devel] " christophe varoqui
2004-03-30 17:03 ` Justin T. Gibbs
2004-03-30 17:15 ` Jeff Garzik
2004-03-30 17:35 ` Justin T. Gibbs
2004-03-30 17:46 ` Jeff Garzik
2004-03-30 18:04 ` Justin T. Gibbs
2004-03-30 21:47 ` Jeff Garzik
2004-03-30 22:12 ` Justin T. Gibbs
2004-03-30 22:34 ` Jeff Garzik
2004-03-30 18:11 ` Bartlomiej Zolnierkiewicz
2004-03-25 22:59 ` Justin T. Gibbs
2004-03-25 23:44 ` Lars Marowsky-Bree
2004-03-26 0:03 ` Justin T. Gibbs
[not found] <1AOTW-4Vx-7@gated-at.bofh.it>
[not found] ` <1AOTW-4Vx-5@gated-at.bofh.it>
2004-03-18 1:33 ` Andi Kleen
2004-03-18 2:00 ` Jeff Garzik
2004-03-20 9:58 ` Jamie Lokier
-- strict thread matches above, loose matches on Subject: below --
2004-03-17 18:14 Justin T. Gibbs
2004-03-17 19:18 ` Jeff Garzik
2004-03-17 19:32 ` Christoph Hellwig
2004-03-17 20:02 ` Jeff Garzik
2004-03-17 21:18 ` Scott Long
2004-03-17 21:35 ` Jeff Garzik
2004-03-17 21:45 ` Bartlomiej Zolnierkiewicz
2004-03-18 0:23 ` Scott Long
2004-03-18 1:55 ` Bartlomiej Zolnierkiewicz
2004-03-18 6:38 ` Stefan Smietanowski
2004-03-20 13:07 ` Arjan van de Ven
2004-03-21 23:42 ` Scott Long
2004-03-22 9:05 ` Arjan van de Ven
2004-03-22 21:59 ` Scott Long
2004-03-23 6:48 ` Arjan van de Ven
2004-03-18 1:56 ` viro
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