Hello folks,
I am experiencing a weird problem at bootup with large RAID-6 arrays.
After Googling around (a lot) I find that others are having the same
issues with CentOS/RHEL/Ubuntu/whatever. In my case it's Scientific
Linux-6 which should behave the same way as CentOS-6. I had the same
problem with the RHEL-6 evaluation version. I'm posting this question
to the SL mailing list as well.
For some reason, each time I boot the server a random number of RAID
arrays will come up with the hot-spare missing. This occurs with
hot-spare components only, never with the active components. Once in a
while I'm lucky enough to have all components come up correctly when the
system boots. Which hot spares fail to be configured is completely random.
I have 12 2TB drives, each divided into 4 primary partitions, and
configured as 8 partitionable MD arrays. All drives are partitioned
exactly the same way. Each R6 array consists of 5 components
(partitions) plus a hot-spare. The small RAID-1 host OS array never has
a problem with its hot spare.
The predominant theory via Google is that there's a race condition at
boot time between full enumeration of all disk partitions and mdadm
assembling the arrays.
Does anyone know of a way to have mdadm delay its assembly until all
partitions are enumerated? Even if it's simply to insert a
several-second wait time, that would probably work. My knowledge of the
internal workings of the boot process isn't good enough to know where to
look.
I tried to issue 'mdadm -A -s /dev/md/md_dXX' after booting, but all it
does is complain about "No suitable drives found for /dev....."
Here is the mdadm.conf file:
-------------------------------------
MAILADDR root
PROGRAM /root/bin/record_md_events.sh
DEVICE partitions
##DEVICE /dev/sd* <<---- this didn't help.
AUTO +imsm +1.x -all
## Host OS root arrays:
ARRAY /dev/md0
metadata=1.0 num-devices=2 spares=1
UUID=75941adb:33e8fa6a:095a70fd:6fe72c69
ARRAY /dev/md1
metadata=1.1 num-devices=2 spares=1
UUID=7a96d82d:bd6480a2:7433f1c2:947b84e9
ARRAY /dev/md2
metadata=1.1 num-devices=2 spares=1
UUID=ffc6070d:e57a675e:a1624e53:b88479d0
## Partitionable arrays on LSI controller:
ARRAY /dev/md/md_d10
metadata=1.2 num-devices=5 spares=1
UUID=135f0072:90551266:5d9a126a:011e3471
ARRAY /dev/md/md_d11
metadata=1.2 num-devices=5 spares=1
UUID=59e05755:5b3ec51e:e3002cfd:f0720c38
ARRAY /dev/md/md_d12
metadata=1.2 num-devices=5 spares=1
UUID=7916eb13:cd5063ba:a1404cd7:3b65a438
ARRAY /dev/md/md_d13
metadata=1.2 num-devices=5 spares=1
UUID=9a767e04:e4e56a9d:c369d25c:9d333760
## Partitionable arrays on Tempo controllers:
ARRAY /dev/md/md_d20
metadata=1.2 num-devices=5 spares=1
UUID=1d5a3c32:eb9374ac:eff41754:f8a176c1
ARRAY /dev/md/md_d21
metadata=1.2 num-devices=5 spares=1
UUID=38ffe8c9:f3922db9:60bb1522:80fea016
ARRAY /dev/md/md_d22
metadata=1.2 num-devices=5 spares=1
UUID=ebb4ea67:b31b2105:498d81af:9b4f45d3
ARRAY /dev/md/md_d23
metadata=1.2 num-devices=5 spares=1
UUID=da07407f:deeb8906:7a70ae82:6b1d8c4a
-------------------------------------
Your suggestions are most welcome ... thanks.
Chuck
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