Re: Raid 5 array problem: 2 disks became spare in stead of member.

["aziro.linux.adm" <aziro.linux.adm@gmail.com>]

Tom De Clercq wrote:

> Hi all,
>
> First of all the best wishes for 2006.
>
> I am searching for a solution for my raid since last Thursday.  What 
> just happened I didn't know for sure, only thing I could see was that 
> my server rebooted multiple times and my raid-5 array went offline.
>
> Os debian stable: Linux tigger.tomsworld.local 2.6.11 #5 SMP Sun Jul 
> 24 23:55:45 CEST 2005 i686 GNU/Linux
> Mdadm upgraded to the currently lastest stable version:
> root@tigger:/home/tom# mdadm -V
> mdadm - v2.2 - 5 December 2005
>
>
> It is a raid-5 array 3*160 GB ATA disk. (mdadm output on the end of 
> this mail)
>
> But now at the moment 2 drives of the array are marked as spare.  I 
> googled & searched the archives of this list but nothing seems to 
> resolve the problem.
>
>
> I tried booting with only the disks marked as "Spare", but the array 
> wouldn't come up either.
> Tried to boot with the 1 disk of the array one other: same result.
>
> I'm trying to force the spare disk into being an array member again.
>
> Could someone of you give me any idea how I could resolve this matter?
>
> Some info:
>
> /etc/raidtab
>
> raiddev /dev/md0
> raid-level 5
> nr-raid-disks 3
> nr-spare-disks 0
> persistent-superblock 1
> parity-algorithm left-symmetric
> chunk-size 32
> device /dev/hde1
> raid-disk 0
> device /dev/hdf1
> raid-disk 1
> device /dev/hdh1
> raid-disk 2
>
>
> root@tigger:/tmp/mdctl-0.5# mdadm --examine /dev/hde1
> /dev/hde1:
> Magic : a92b4efc
> Version : 00.90.01
> UUID : 6644de41:0e38ffb1:e5f77c38:825553ae
> Creation Time : Tue May 31 21:24:31 2005
> Raid Level : raid5
> Raid Devices : 3
> Total Devices : 3
> Preferred Minor : 0
>
> Update Time : Thu Dec 29 11:33:33 2005
> State : clean
> Active Devices : 1
> Working Devices : 3
> Failed Devices : 2
> Spare Devices : 2
> Checksum : 1ed2c2c5 - correct
> Events : 0.75536395
>
> Layout : left-symmetric
> Chunk Size : 32K
>
> Number Major Minor RaidDevice State
> this 3 33 1 3 spare /dev/hde1
>
> 0 0 33 65 0 active sync /dev/hdf1
> 1 1 0 0 1 faulty removed
> 2 2 0 0 2 faulty removed
> 3 3 33 1 3 spare /dev/hde1
> 4 4 34 65 4 spare /dev/hdh1
> root@tigger:/tmp/mdctl-0.5# mdadm --examine /dev/hdf1
> /dev/hdf1:
> Magic : a92b4efc
> Version : 00.90.01
> UUID : 6644de41:0e38ffb1:e5f77c38:825553ae
> Creation Time : Tue May 31 21:24:31 2005
> Raid Level : raid5
> Raid Devices : 3
> Total Devices : 3
> Preferred Minor : 0
>
> Update Time : Thu Dec 29 11:33:33 2005
> State : clean
> Active Devices : 1
> Working Devices : 3
> Failed Devices : 2
> Spare Devices : 2
> Checksum : 1ed2c301 - correct
> Events : 0.75536395
>
> Layout : left-symmetric
> Chunk Size : 32K
>
> Number Major Minor RaidDevice State
> this 0 33 65 0 active sync /dev/hdf1
>
> 0 0 33 65 0 active sync /dev/hdf1
> 1 1 0 0 1 faulty removed
> 2 2 0 0 2 faulty removed
> 3 3 33 1 1 spare /dev/hde1
> 4 4 34 65 2 spare /dev/hdh1
> root@tigger:/tmp/mdctl-0.5# mdadm --examine /dev/hdh1
> /dev/hdh1:
> Magic : a92b4efc
> Version : 00.90.01
> UUID : 6644de41:0e38ffb1:e5f77c38:825553ae
> Creation Time : Tue May 31 21:24:31 2005
> Raid Level : raid5
> Raid Devices : 3
> Total Devices : 3
> Preferred Minor : 0
>
> Update Time : Thu Dec 29 11:33:33 2005
> State : clean
> Active Devices : 1
> Working Devices : 3
> Failed Devices : 2
> Spare Devices : 2
> Checksum : 1ed2c308 - correct
> Events : 0.75536395
>
> Layout : left-symmetric
> Chunk Size : 32K
>
> Number Major Minor RaidDevice State
> this 4 34 65 4 spare /dev/hdh1
>
> 0 0 33 65 0 active sync /dev/hdf1
> 1 1 0 0 1 faulty removed
> 2 2 0 0 2 faulty removed
> 3 3 33 1 3 spare /dev/hde1
> 4 4 34 65 4 spare /dev/hdh1
> root@tigger:/tmp/mdctl-0.5#
> root@tigger:/tmp/mdctl-0.5# mdadm --create /dev/md0 -l5 -n3 /dev/hde1 
> /dev/hdf1 /dev/hdh1
> mdadm: /dev/hde1 appears to be part of a raid array:
> level=5 devices=3 ctime=Tue May 31 21:24:31 2005
> mdadm: /dev/hdf1 appears to contain an ext2fs file system
> size=320159104K mtime=Thu Dec 29 09:51:49 2005
> mdadm: /dev/hdf1 appears to be part of a raid array:
> level=5 devices=3 ctime=Tue May 31 21:24:31 2005
> mdadm: /dev/hdh1 appears to contain an ext2fs file system
> size=341131652K mtime=Mon Dec 20 21:49:29 1971
> mdadm: /dev/hdh1 appears to be part of a raid array:
> level=5 devices=3 ctime=Tue May 31 21:24:31 2005
> Continue creating array? n
> mdadm: create aborted.
> root@tigger:/tmp/mdctl-0.5#
>
>
> Thanks a lot in advance.
>
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Hi, Tom
I think you must tray with :

mdadm -A /dev/md0 -f /dev/hd[efh]1

or more humman readable:

mdadm --assemble /dev/md0 --force /dev/hd[efh]1

This way mdadm will assemble the your existing array, but for  RAID5  
mdadm require minimum 3 + 1 spare disk I think, but not absolutly sure:)
May mdadm require minimum 3 + 1 spare only with --create mode, to create 
RAID level 5.

Good luck!