From: Bill Davidsen <davidsen@tmr.com>
To: David <lists@edeca.net>
Cc: linux-raid@vger.kernel.org
Subject: Re: Swap initialised as an md?
Date: Fri, 23 Mar 2007 16:22:09 -0400 [thread overview]
Message-ID: <460436F1.2080003@tmr.com> (raw)
In-Reply-To: <20061110102955.ljws9mgxf4o4kgw8@my.pengus.net>
David wrote:
> I have two devices mirrored which are partitioned like this:
>
> Device Boot Start End Blocks Id System
> /dev/sda1 * 63 30716279 15358108+ fd Linux raid
> autodetect
> /dev/sda2 30716280 71682029 20482875 fd Linux raid
> autodetect
> /dev/sda3 71682030 112647779 20482875 fd Linux raid
> autodetect
> /dev/sda4 112647780 156248189 21800205 5 Extended
> /dev/sda5 112647843 122881184 5116671 82 Linux swap /
> Solaris
> /dev/sda6 122881248 156248189 16683471 fd Linux raid
> autodetect
>
> My aim was to have the two swap partitions both mounted, no RAID (as I
> didn't see any benefit to that, but if I'm wrong then I'd appreciate
> being told!). However it seems that sda5 seems to be recognised as an
> md anyway at boot, so swapon does not work correctly. When
> initialising the partitions with mkswap, the RAID array is confused
> and refuses to boot until the superblocks are fixed.
If you use RAID0 on an array it will be faster (usually) than just
partitions, but any process with swapped pages will crash if you lose
either drive. With RAID1 operation will be more reliable but no faster.
If you use RAID10 the array will be faster and more reliable, but most
recovery CDs don't know about RAID10 swap. Any reliable swap will also
have the array size smaller than the sum of the partitions (you knew that).
--
bill davidsen <davidsen@tmr.com>
CTO TMR Associates, Inc
Doing interesting things with small computers since 1979
next prev parent reply other threads:[~2007-03-23 20:22 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-11-10 10:29 Swap initialised as an md? David
2006-11-10 11:55 ` Mogens Kjaer
2006-11-12 14:03 ` Gabor Gombas
2007-03-23 14:56 ` Grow a RAID-6 ? Gordon Henderson
2007-03-23 15:31 ` Mattias Wadenstein
2007-03-23 16:34 ` Gordon Henderson
2007-03-24 2:20 ` Daniel Korstad
2007-03-23 20:22 ` Bill Davidsen [this message]
2007-03-23 20:35 ` Swap initialised as an md? Michael Tokarev
2007-03-26 3:45 ` Bill Davidsen
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