> > Date: Fri, 18 Feb 2011 21:49:16 +0100
> >
> > > Dnia 2011-02-18, pią o godzinie 15:08 -0500, Mike Viau pisze:
> > > I was wondering if anyone had come across an issue where after
> > > rebooting the system, mdadm fails to reassemble an entire raid 5 array
> > > with all the drives. I am getting the array up with just /dev/sda and
> > > /dev/sdb, but the array is degraded as a consequence to missing
> > > /dev/sdd (which I assume has become the parity drive).
> >
> > There is no such thing as a parity drive in raid5, everything (parity
> > data, too) is spread out evenly over all of the disks.
> >
>
> Hmm, that makes more sense hence distributed parity).
>
> > Please post the output of `mdadm --examine /dev/sd{a,b,d}1` and check
> > your logs to see if there are any mentions of why the array isn't
> > assembled on boot.
> >
>
> mdadm --examine /dev/sd{a,b,d}1
> /dev/sda1:
> Magic : a92b4efc
> Version : 1.2
> Feature Map : 0x0
> Array UUID : 7d8a7c68:95a230d0:0a8f6e74:4c8f81e9
> Name : XEN-HOST:0 (local to host XEN-HOST)
> Creation Time : Mon Dec 20 09:48:07 2010
> Raid Level : raid5
> Raid Devices : 3
>
> Avail Dev Size : 1953517954 (931.51 GiB 1000.20 GB)
> Array Size : 3907035136 (1863.02 GiB 2000.40 GB)
> Used Dev Size : 1953517568 (931.51 GiB 1000.20 GB)
> Data Offset : 2048 sectors
> Super Offset : 8 sectors
> State : clean
> Device UUID : 25f4baf0:9a378d2c:16a87f0c:ff89b2c8
>
> Update Time : Fri Feb 18 16:32:19 2011
> Checksum : 37383bee - correct
> Events : 32184
>
> Layout : left-symmetric
> Chunk Size : 512K
>
> Device Role : Active device 0
> Array State : AAA ('A' == active, '.' == missing)
> /dev/sdb1:
> Magic : a92b4efc
> Version : 1.2
> Feature Map : 0x0
> Array UUID : 7d8a7c68:95a230d0:0a8f6e74:4c8f81e9
> Name : XEN-HOST:0 (local to host XEN-HOST)
> Creation Time : Mon Dec 20 09:48:07 2010
> Raid Level : raid5
> Raid Devices : 3
>
> Avail Dev Size : 1953517954 (931.51 GiB 1000.20 GB)
> Array Size : 3907035136 (1863.02 GiB 2000.40 GB)
> Used Dev Size : 1953517568 (931.51 GiB 1000.20 GB)
> Data Offset : 2048 sectors
> Super Offset : 8 sectors
> State : clean
> Device UUID : f20ab5fd:1f141cae:e0547278:d6cf063e
>
> Update Time : Fri Feb 18 16:32:19 2011
> Checksum : a70821e2 - correct
> Events : 32184
>
> Layout : left-symmetric
> Chunk Size : 512K
>
> Device Role : Active device 1
> Array State : AAA ('A' == active, '.' == missing)
> /dev/sdd1:
> Magic : a92b4efc
> Version : 1.2
> Feature Map : 0x2
> Array UUID : 7d8a7c68:95a230d0:0a8f6e74:4c8f81e9
> Name : XEN-HOST:0 (local to host XEN-HOST)
> Creation Time : Mon Dec 20 09:48:07 2010
> Raid Level : raid5
> Raid Devices : 3
>
> Avail Dev Size : 1953521072 (931.51 GiB 1000.20 GB)
> Array Size : 3907035136 (1863.02 GiB 2000.40 GB)
> Used Dev Size : 1953517568 (931.51 GiB 1000.20 GB)
> Data Offset : 2048 sectors
> Super Offset : 8 sectors
> Recovery Offset : 610474280 sectors
> State : clean
> Device UUID : 33d70114:ffdc4fcc:2c8d65ba:ab50bab2
>
> Update Time : Fri Feb 18 16:32:19 2011
> Checksum : b692957e - correct
> Events : 32184
>
> Layout : left-symmetric
> Chunk Size : 512K
>
> Device Role : Active device 2
> Array State : AAA ('A' == active, '.' == missing)
>
>
>
> The array actually does assemble on boot, but the /dev/sdd1 partition
> is not added automatically, and I am not sure why?
>
> >
> > Have you tried booting in single user mode (I assume this drive isn't
> > your boot drive?) and try to assemble the array by hand? Have you seen
> > any errors?
> >
>
What specific command should I use to assemble the array by hand? I see that there are assemble and incremental assemble commands. I'd also assume I should increase the verbosity to see what is going on.
Does anyone think that trying to re-build this raid 5 array would be a possible way to fix the removed drive problem on boot?
I read in the man page under the section for build:
"cannot differentiate between initial creation and subsequent assembly of an array.
It also cannot perform any checks that appropriate components have been requested. Because of
this, the Build mode should only be used together with a complete understanding of what you are doing."
Therefor I am cautious to proceed without some advice first...
Thanks.
> The array was initially created about a month ago, below are the mdadm
> events in my syslog. A couple questions arise:
>
> 1) If mdadm initially created the array as md127, and then I declared
> it as md0 in mdadm.conf as:
>
> # definitions of existing MD arrays
> ARRAY /dev/md/0 metadata=1.2 UUID=7d8a7c68:95a230d0:0a8f6e74:4c8f81e9
> name=XEN-HOST:0
>
>
> 2) If sdd was an always connected usb enclosure connected hard drive as
> apposed to /dev/sda and /dev/sdb being directly connected SATA drives.
>
>
> Would either of these cause the problem such as the subject of this thread?
>
>
> cat /var/log/syslog | grep mdadm
> Jan 30 00:57:01 XEN-HOST /USR/SBIN/CRON[6944]: (root) CMD (if [ -x
> /usr/share/mdadm/checkarray ] && [ $(date +%d) -le 7 ]; then
> /usr/share/mdadm/checkarray --cron --all --idle --quiet; fi)
> Jan 30 22:33:48 XEN-HOST mdadm[25684]: NewArray event detected on md
> device /dev/md127
> Jan 30 22:33:48 XEN-HOST mdadm[25684]: DegradedArray event detected on
> md device /dev/md127
> Jan 30 22:45:13 XEN-HOST mdadm[1883]: NewArray event detected on md
> device /dev/md127
> Jan 30 22:45:15 XEN-HOST mdadm[1883]: DegradedArray event detected on
> md device /dev/md127
> Jan 30 23:29:31 XEN-HOST mdadm[1930]: DegradedArray event detected on
> md device /dev/md/0
> Jan 30 23:33:51 XEN-HOST mdadm[1889]: DegradedArray event detected on
> md device /dev/md/0
> Jan 30 23:38:32 XEN-HOST mdadm[1889]: RebuildStarted event detected on
> md device /dev/md/0
> Jan 31 01:51:53 XEN-HOST mdadm[1889]: Rebuild20 event detected on md
> device /dev/md/0
> Jan 31 04:05:13 XEN-HOST mdadm[1889]: Rebuild41 event detected on md
> device /dev/md/0
> Jan 31 06:18:34 XEN-HOST mdadm[1889]: Rebuild62 event detected on md
> device /dev/md/0
> Jan 31 08:15:15 XEN-HOST mdadm[1889]: Rebuild80 event detected on md
> device /dev/md/0
> Jan 31 10:15:50 XEN-HOST mdadm[1889]: RebuildFinished event detected on
> md device /dev/md/0
> Jan 31 10:15:50 XEN-HOST mdadm[1889]: SpareActive event detected on md
> device /dev/md/0
> Feb 6 00:57:01 XEN-HOST /USR/SBIN/CRON[13578]: (root) CMD (if [ -x
> /usr/share/mdadm/checkarray ] && [ $(date +%d) -le 7 ]; then
> /usr/share/mdadm/checkarray --cron --all --idle --quiet; fi)
> Feb 6 00:57:01 XEN-HOST mdadm[1889]: RebuildStarted event detected on
> md device /dev/md/0
> Feb 6 02:37:02 XEN-HOST mdadm[1889]: Rebuild21 event detected on md
> device /dev/md/0
> Feb 6 04:17:02 XEN-HOST mdadm[1889]: Rebuild42 event detected on md
> device /dev/md/0
> Feb 6 05:40:23 XEN-HOST mdadm[1889]: Rebuild60 event detected on md
> device /dev/md/0
> Feb 6 07:20:23 XEN-HOST mdadm[1889]: Rebuild81 event detected on md
> device /dev/md/0
> Feb 6 08:44:40 XEN-HOST mdadm[1889]: RebuildFinished event detected on
> md device /dev/md/0
> Feb 6 23:11:07 XEN-HOST mdadm[1887]: DegradedArray event detected on
> md device /dev/md/0
> Feb 8 08:51:53 XEN-HOST mdadm[1887]: RebuildStarted event detected on
> md device /dev/md/0
> Feb 8 11:05:13 XEN-HOST mdadm[1887]: Rebuild20 event detected on md
> device /dev/md/0
> Feb 8 13:18:34 XEN-HOST mdadm[1887]: Rebuild41 event detected on md
> device /dev/md/0
> Feb 8 15:15:14 XEN-HOST mdadm[1887]: Rebuild60 event detected on md
> device /dev/md/0
> Feb 8 17:28:35 XEN-HOST mdadm[1887]: Rebuild81 event detected on md
> device /dev/md/0
> Feb 8 19:26:32 XEN-HOST mdadm[1887]: RebuildFinished event detected on
> md device /dev/md/0
> Feb 8 19:26:32 XEN-HOST mdadm[1887]: SpareActive event detected on md
> device /dev/md/0
> Feb 13 00:57:01 XEN-HOST /USR/SBIN/CRON[12933]: (root) CMD (if [ -x
> /usr/share/mdadm/checkarray ] && [ $(date +%d) -le 7 ]; then
> /usr/share/mdadm/checkarray --cron --all --idle --quiet; fi)
> Feb 18 12:19:31 XEN-HOST mdadm[1864]: DegradedArray event detected on
> md device /dev/md/0
> Feb 18 12:23:07 XEN-HOST mdadm[1613]: DegradedArray event detected on
> md device /dev/md/0
> Feb 18 12:26:24 XEN-HOST mdadm[1767]: DegradedArray event detected on
> md device /dev/md/0
> Feb 18 12:50:53 XEN-HOST mdadm[1767]: RebuildStarted event detected on
> md device /dev/md/0
> Feb 18 15:04:14 XEN-HOST mdadm[1767]: Rebuild21 event detected on md
> device /dev/md/0
>
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