Message-ID: <46605E24.7070508@emolecules.com>
Date: Fri, 01 Jun 2007 10:57:56 -0700
From: Craig James <craig_james@emolecules.com>
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CC: pgsql-performance@postgresql.org
Subject: Autodetect of software RAID1+0 fails
References: <C3E62232E3BCF24CBA20D72BFDCB6BF804382037@MI8NYCMAIL08.Mi8.com>
	<op.ts5b3kikcigqcu@apollo13>
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Apologies for a somewhat off-topic question, but...

The Linux kernel doesn't properly detect my software RAID1+0 when I boot up.  It detects the two RAID1 arrays, the partitions of which are marked properly.  But it can't find the RAID0 on top of that, because there's no corresponding device to auto-detect.  The result is that it creates /dev/md0 and /dev/md1 and assembles the RAID1 devices on bootup, but /dev/md2 isn't created, so the RAID0 can't be assembled at boot time.

Here's what it looks like:

$ cat /proc/mdstat 
Personalities : [raid0] [raid1] 
md2 : active raid0 md0[0] md1[1]
      234436224 blocks 64k chunks
      
md1 : active raid1 sde1[1] sdc1[2]
      117218176 blocks [2/2] [UU]
      
md0 : active raid1 sdd1[1] sdb1[0]
      117218176 blocks [2/2] [UU]

$ uname -r
2.6.12-1.1381_FC3

After a reboot, I always have to do this:

      mknod /dev/md2 b 9 2
      mdadm --assemble /dev/md2 /dev/md0 /dev/md1
      mount /dev/md2

What am I missing here?

Thanks,
Craig