On Thu, 30 Dec 2010 16:20:58 -0700 Jim Schatzman
<james.schatzman@xxxxxxxxxxxxxxxx> wrote:
> When I rebooted my server yesterday, not all the RAIDs came up. There were no errors in the system log. All devices appear to be working correctly. There is no evidence of hardware errors or data corruption.
>
> To prevent mdadm from failing RAID drives, I removed the RAID entries from /etc/mdadm.conf, and I have a cron script that does things like
>
> mdadm -A --no-degraded /dev/md5 --uuid 291655c3:b6c334ff:8dfe69a4:447f777b
> mdadm: /dev/md5 assembled from 2 drives (out of 4), but not started.
>
> The question is, why did mdadm assemble only 2 drives, when all 4 drives appear to be fine? The same problem occurred for 4 RAIDs, each with similar geometry, and using the same 4 physical drives.
Add a '--verbose' to the '-A' command. Hopefully it will reveal something
interesting.
NeilBrown
>
> Here is the status of all 4 partitions that should have been assembled into /dev/md5:
>
> [root@l1 ~]# mdadm -E /dev/sda5
> /dev/sda5:
> Magic : a92b4efc
> Version : 1.2
> Feature Map : 0x0
> Array UUID : 291655c3:b6c334ff:8dfe69a4:447f777b
> Name : l1.fu-lab.com:5 (local to host l1.fu-lab.com)
> Creation Time : Thu Sep 23 13:41:31 2010
> Raid Level : raid5
> Raid Devices : 4
>
> Avail Dev Size : 957214849 (456.44 GiB 490.09 GB)
> Array Size : 2871641088 (1369.31 GiB 1470.28 GB)
> Used Dev Size : 957213696 (456.44 GiB 490.09 GB)
> Data Offset : 2048 sectors
> Super Offset : 8 sectors
> State : clean
> Device UUID : 4088b63f:68d66426:a2abd280:28476493
>
> Update Time : Wed Dec 22 08:27:57 2010
> Checksum : 48e371ac - correct
> Events : 339
>
> Layout : left-symmetric
> Chunk Size : 512K
>
> Device Role : Active device 0
> Array State : AAAA ('A' == active, '.' == missing)
> [root@l1 ~]# mdadm -E /dev/sdi5
> /dev/sdi5:
> Magic : a92b4efc
> Version : 1.2
> Feature Map : 0x0
> Array UUID : 291655c3:b6c334ff:8dfe69a4:447f777b
> Name : l1.fu-lab.com:5 (local to host l1.fu-lab.com)
> Creation Time : Thu Sep 23 13:41:31 2010
> Raid Level : raid5
> Raid Devices : 4
>
> Avail Dev Size : 957214849 (456.44 GiB 490.09 GB)
> Array Size : 2871641088 (1369.31 GiB 1470.28 GB)
> Used Dev Size : 957213696 (456.44 GiB 490.09 GB)
> Data Offset : 2048 sectors
> Super Offset : 8 sectors
> State : clean
> Device UUID : bfc9fe39:c3e40f6a:7418831b:87e08f16
>
> Update Time : Wed Dec 22 08:27:57 2010
> Checksum : a4b2c7b7 - correct
> Events : 339
>
> Layout : left-symmetric
> Chunk Size : 512K
>
> Device Role : Active device 1
> Array State : AAAA ('A' == active, '.' == missing)
> [root@l1 ~]# mdadm -E /dev/sdj5
> /dev/sdj5:
> Magic : a92b4efc
> Version : 1.2
> Feature Map : 0x0
> Array UUID : 291655c3:b6c334ff:8dfe69a4:447f777b
> Name : l1.fu-lab.com:5 (local to host l1.fu-lab.com)
> Creation Time : Thu Sep 23 13:41:31 2010
> Raid Level : raid5
> Raid Devices : 4
>
> Avail Dev Size : 957214849 (456.44 GiB 490.09 GB)
> Array Size : 2871641088 (1369.31 GiB 1470.28 GB)
> Used Dev Size : 957213696 (456.44 GiB 490.09 GB)
> Data Offset : 2048 sectors
> Super Offset : 8 sectors
> State : clean
> Device UUID : 3e1f7e30:730c70c0:c2770470:8e40ea84
>
> Update Time : Wed Dec 22 08:27:57 2010
> Checksum : b46e043d - correct
> Events : 339
>
> Layout : left-symmetric
> Chunk Size : 512K
>
> Device Role : Active device 2
> Array State : AAAA ('A' == active, '.' == missing)
> [root@l1 ~]# mdadm -E /dev/sdk5
> /dev/sdk5:
> Magic : a92b4efc
> Version : 1.2
> Feature Map : 0x0
> Array UUID : 291655c3:b6c334ff:8dfe69a4:447f777b
> Name : l1.fu-lab.com:5 (local to host l1.fu-lab.com)
> Creation Time : Thu Sep 23 13:41:31 2010
> Raid Level : raid5
> Raid Devices : 4
>
> Avail Dev Size : 957214849 (456.44 GiB 490.09 GB)
> Array Size : 2871641088 (1369.31 GiB 1470.28 GB)
> Used Dev Size : 957213696 (456.44 GiB 490.09 GB)
> Data Offset : 2048 sectors
> Super Offset : 8 sectors
> State : clean
> Device UUID : 5acc120a:e7197136:7d7a29c2:971e410d
>
> Update Time : Wed Dec 22 08:27:57 2010
> Checksum : de7f9f92 - correct
> Events : 339
>
> Layout : left-symmetric
> Chunk Size : 512K
>
> Device Role : Active device 3
> Array State : AAAA ('A' == active, '.' == missing)
>
>
> I could try assembling the RAID with other command syntaxes (such as by listing all the partitions/devices manually). However, I see no reason why this should be necessary.
>
> Also,
>
> mdadm -V
> mdadm - v3.1.2 - 10th March 2010
>
> What is going on?
>
> Thanks!
>
> Jim
>
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