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Old 01-18-2010, 03:46 PM   #1
Registered: Feb 2004
Location: Chaska, MN
Distribution: Fedora
Posts: 195

Rep: Reputation: 31
mdadm won't rebuild

I've been having some serious issues with my RAID 1+0 array in mdadm. Here is the situation:

*Original array had 4 500GB disks.
*2 drives failed, one on each side of stripe.
*Data is backed up and running on another array, so this array is not in use.
*When I try to add a disk to the array, it stops very soon after starting.

cat /proc/mdstat:
Personalities : [raid1] [raid0]
md125 : active raid0 md126[0] md127[1]
976767744 blocks 64k chunks

md126 : active raid1 sdb1[0]
488383936 blocks [2/1] [U_]

md127 : active raid1 sdc1[2] sde1[1]
488383936 blocks [2/1] [_U]

unused devices: <none>

mdadm --detail /dev/md127
Version : 0.90
Creation Time : Thu Jan 8 16:18:42 2009
Raid Level : raid1
Array Size : 488383936 (465.76 GiB 500.11 GB)
Used Dev Size : 488383936 (465.76 GiB 500.11 GB)
Raid Devices : 2
Total Devices : 2
Preferred Minor : 127
Persistence : Superblock is persistent

Update Time : Mon Jan 18 15:41:53 2010
State : clean, degraded
Active Devices : 1
Working Devices : 2
Failed Devices : 0
Spare Devices : 1

UUID : 1102d292:565d896d:990d6c03:66fab5e4
Events : 0.5547582

Number Major Minor RaidDevice State
2 8 33 0 spare rebuilding /dev/sdc1
1 8 65 1 active sync /dev/sde1

Is there any way to force /dev/md127 to rebuild? Like I stops rebuilding after about 3%. What gives?

Thanks for your continued help, LQ,


Last edited by Cottsay; 01-18-2010 at 03:48 PM. Reason: More Info
Old 01-19-2010, 01:15 PM   #2
Senior Member
Registered: Dec 2008
Location: Louisville, OH
Distribution: Debian, CentOS, Slackware, RHEL, Gentoo
Posts: 1,833

Rep: Reputation: 167Reputation: 167
Have you replaced the failed disks yet? It doesn't appear as if at least for 126 that it sees the new partition it needs to rebuild on. 127 seems to see it, but is that the old disk that failed or the new one replacing it?

I'd make sure I had some real good backups (verifying them, maybe making a second set) before doing much if you lost one on each stripe already.
Old 01-19-2010, 02:46 PM   #3
Registered: Feb 2004
Location: Chaska, MN
Distribution: Fedora
Posts: 195

Original Poster
Rep: Reputation: 31
I have not gotten a hold of a matching replacement disk for 126 yet. I can safely say that all of the data is completely backed up. The real question that I have pertains to what sdc1 is being used for in 127? It isn't marked as "failed," but it won't seem to synchronize it with the array. In the mdadm --detail, "STATE" should have "rebuilding" in it, and it doesn't. sdc1 is marked as "spare rebuilding" and it never gets to "active sync" and I don't know why...Thanks very much for your interest in my little predicament...



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