Date: Fri, 23 May 2003 16:38:31 +0200
To: Seth Mos <knuffie@xs4all.nl>
Cc: linux-xfs@oss.sgi.com
Subject: Re: Problem with XFS on software RAID1
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From: Dariush Pietrzak <eyck@forumakad.pl>
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On Fri, May 23, 2003 at 04:16:02PM +0200, Seth Mos wrote:
> mount /dev/sda1 under /mnt/sda1
Exactly.. that part doesen't work with XFS for me, although I see no reason for it
to fail ( other than that raw partition contains raid superblock, and it
works fine with other filesystems ).
 For this part you can always created degraded array with non-existant
failed disk and then mount this. 
But I still have no idea how one could migrate from simple filesystem to
RAID1.

> Linux software raid 1 uses read balancing to give higher read speeds (raid 
> 0 like), however the data on both disks must be the _exact_ same to the 
> bit. Mounting the disk without the raid layer once will make them different 
 I don't know the code, but if i understand correctly then untill the array
is resynced it works in degraded mode and should read only from working
partition.

  I think this:
harybda:~# cat /proc/mdstat 
Personalities : [raid1] 
read_ahead 1024 sectors
md0 : active raid1 sdb6[2] sda6[0]
      714752 blocks [2/1] [U_]
            [>....................]  recovery =  2.7% (19456/714752)
	    finish=1.7min speed=6485K/sec

would mean that freshly addedd sdb6 part is not operational ( "_" as opposed
to "U" ) until it has been fully resynced.

 The other thing is that I'm working here with clean filesystems so no
log-reply should occur ( i think ).
  
-- 
Dariush Pietrzak,
She swore and she cursed, that she never would deceive me
Key fingerprint = 40D0 9FFB 9939 7320 8294  05E0 BCC7 02C4 75CC 50D9