On Sun, 14 Dec 2008, nterry wrote:
Michal Soltys wrote:
nterry wrote:
Hi. I hope someone can tell me what I have done wrong. I have a 4 disk
Raid 5 array running on Fedora9. I've run this array for 2.5 years with
no issues. I recently rebooted after upgrading to Kernel 2.6.27.7. When
I did this I found that only 3 of my disks were in the array. When I
examine the three active elements of the array (/dev/sdd1, /dev/sde1,
/dev/sdc1) they all show that the array has 3 drives and one missing.
When I examine the missing drive it shows that all members of the array
are present, which I don't understand! When I try to add the missing drive
back is says the device is busy. Please see below and let me know what I
need to do to get this working again. Thanks Nigel:
==================================================================
[root@homepc ~]# cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active raid5 sdd1[0] sdc1[3] sde1[1]
735334656 blocks level 5, 128k chunk, algorithm 2 [4/3] [UU_U]
md_d0 : inactive sdb[2](S)
245117312 blocks
unused devices: <none>
[root@homepc ~]#
For some reason, it looks like you have 2 raid arrays visible - md0 and
md_d0. The latter took sdb (not sdb1) as its component.
sd{c,d,e}1 is in assembeld array (with appropriately updated superblocks),
thus mdadm --examine calls show one device as removed, but sdb is part of
another inactive array, and the superblock is untouched and shows "old"
situation. Note that 0.9 superblock is stored at the end of the device
(see md(4) for details), so its position could be valid for both sdb and
sdb1.
This might be an effect of --incremental assembly mode. Hard to tell more
without seeing startup scripts, mdadm.conf, udev rules, partition layout...
Did upgrade involve anything more besides kernel ?
Stop both arrays, check mdadm.conf, assemble md0 manually (mdadm -A
/dev/md0 /dev/sd{c,d,e}1 ), verify situation with mdadm -D. If everything
looks sane, add /dev/sdb1 to the array. Still, w/o checking out startup
stuff, it might happen again after reboot. Adding DEVICE /dev/sd[bcde]1 to
mdadm.conf might help though.
Wait a bit for other suggestions as well.
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I don't think the Kernel upgrade actually caused the problem. I tried
booting up on an older (2.6.27.5) kernel and that made no difference. I
checked the logs for anything else that might have made a difference, but
couldn't see anything that made any sense to me. I did note that on an
earlier update mdadm was upgraded:
Nov 26 17:08:32 Updated: mdadm-2.6.7.1-1.fc9.x86_64
and I did not reboot after that upgrade
I included my mdadm.conf with the last email and it includes ARRAY /dev/md0
level=raid5 num-devices=4 devices=/dev/sdb1,/dev/sdc1,/dev/sdd1,/dev/sde1
My configuration is just vanilla Fedora9 with the mdadm.conf I sent
I've never had a /dev/md_d0 array, so that must have been automatically
created. I may have had other devices and partitions in /dev/md0 as I know I
had several attempts at getting it working 2.5 years ago, and I had other
issues when Fedora changed device naming, I think at FC7. There is only one
partition on /dev/sdb, see below:
(parted) select /dev/sdb
Using /dev/sdb
(parted) print
Model: ATA Maxtor 6L250R0 (scsi)
Disk /dev/sdb: 251GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Number Start End Size Type File system Flags 1 32.3kB
251GB 251GB primary boot, raid
So it looks like something is creating the /dev/md_d0 and adding /dev/sdb to
it before /dev/md0 gets started.
So I tried:
[root@homepc ~]# mdadm --stop /dev/md_d0
mdadm: stopped /dev/md_d0
[root@homepc ~]# mdadm --add /dev/md0 /dev/sdb1
mdadm: re-added /dev/sdb1
[root@homepc ~]# cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active raid5 sdb1[4] sdd1[0] sdc1[3] sde1[1]
735334656 blocks level 5, 128k chunk, algorithm 2 [4/3] [UU_U]
[>....................] recovery = 0.1% (299936/245111552)
finish=81.6min speed=49989K/sec
unused devices: <none>
[root@homepc ~]#
Great - All working. Then I rebooted and was back to square one with only 3
drives in /dev/md0 and /dev/sdb in /dev/md_d0
So I am still not understanding where
/dev/md_d0 is coming from and although I know how to get things working after
a reboot, clearly this is not a long term solution...
What does:
mdadm --examine --scan
Say?
Are you using a kernel with an initrd+modules or is everything compiled
in?
Justin.
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