Raid 5 events not updates after resync

DISCUSSION John 1 participant 1 message Mar 2, 2014 MD RAID

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John

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2014-03-02 10:33 UTC #0 lore raw

Moving existing raid 5 to new linux install.

Some strange stuff gone on with one array/drive (This is after my latest assemble with the 3 good drives and adding failed drive & allowing resync)

4 Disk array raid 5

mdadm --assemble /dev/md2 /dev/sdc /dev/sda /dev/sdd
mdadm : /dev/md2 assembled from 3 drives - need all 4 drives to assemble (use --run to insist) mdadm --assemble /dev/md2 /dev/sdc /dev/sda /dev/sdd --run
mdadm : /dev/md2 has been started with 3 drives (out of 4)
mdadm -a /dev/md2 /dev/sdb
<resync completes without error a few hours later>

This has been going on for 2-3 re syncs, each time I reboot ends up in same situation. No disk errors in dmesg, resync completes without an issue.. Any ideas?

3 out of 4 disks show events as 506196
1 disk shows events as 184869 (The disk added in as spare, this seems strange to me)

Regards

John

/dev/sda:

          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x0
     Array UUID : 73ea3bd2:50b609a1:768a7e19:ca3ef9f0
           Name : storagepc:raid-2tb

Creation Time : Fri Oct 28 06:31:30 2011
Raid Level : raid5
Raid Devices : 4

Avail Dev Size : 3907027120 (1863.02 GiB 2000.40 GB)

     Array Size : 5860540224 (5589.05 GiB 6001.19 GB)
  Used Dev Size : 3907026816 (1863.02 GiB 2000.40 GB)
    Data Offset : 2048 sectors
   Super Offset : 8 sectors
   Unused Space : before=1968 sectors, after=304 sectors
          State : clean
    Device UUID : 7a9638fc:774dd136:431f0d15:37853f2a

    Update Time : Sun Mar  2 09:19:18 2014
       Checksum : 827e2559 - correct
         Events : 506196

         Layout : left-symmetric
     Chunk Size : 64K

Device Role : Active device 2
Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing)
/dev/sdb:

          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x0
     Array UUID : 73ea3bd2:50b609a1:768a7e19:ca3ef9f0
           Name : storagepc:raid-2tb

Creation Time : Fri Oct 28 06:31:30 2011
Raid Level : raid5
Raid Devices : 4

Avail Dev Size : 3907027120 (1863.02 GiB 2000.40 GB)

     Array Size : 5860540224 (5589.05 GiB 6001.19 GB)

Used Dev Size : 3907026816 (1863.02 GiB 2000.40 GB)
Data Offset : 2048 sectors
Super Offset : 8 sectors
Unused Space : before=1968 sectors, after=304 sectors
State : clean
Device UUID : 14d83150:d2b9ad69:9e004df3:06819bc3

Update Time : Thu Nov 1 08:14:09 2012
Checksum : 7e6700eb - correct
Events : 184869

Layout : left-symmetric
Chunk Size : 64K

Device Role : Active device 0
Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing)
/dev/sdc:

          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x0
     Array UUID : 73ea3bd2:50b609a1:768a7e19:ca3ef9f0
           Name : storagepc:raid-2tb

Creation Time : Fri Oct 28 06:31:30 2011
Raid Level : raid5
Raid Devices : 4

Avail Dev Size : 3907027120 (1863.02 GiB 2000.40 GB)

     Array Size : 5860540224 (5589.05 GiB 6001.19 GB)

Update Time : Sun Mar 2 09:19:18 2014
Checksum : 2dedebed - correct
Events : 506196

Layout : left-symmetric
Chunk Size : 64K

Device Role : Active device 1
Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing)
/dev/sdd:

          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x0
     Array UUID : 73ea3bd2:50b609a1:768a7e19:ca3ef9f0
           Name : storagepc:raid-2tb

Creation Time : Fri Oct 28 06:31:30 2011
Raid Level : raid5
Raid Devices : 4

Avail Dev Size : 3907027120 (1863.02 GiB 2000.40 GB)

     Array Size : 5860540224 (5589.05 GiB 6001.19 GB)
  Used Dev Size : 3907026816 (1863.02 GiB 2000.40 GB)
    Data Offset : 2048 sectors
   Super Offset : 8 sectors
   Unused Space : before=1968 sectors, after=304 sectors
          State : clean
    Device UUID : 090464a9:11cc8cf4:e22aa863:7d880f58

    Update Time : Sun Mar  2 09:19:18 2014
       Checksum : 69d02087 - correct
         Events : 506196

         Layout : left-symmetric
     Chunk Size : 64K

Device Role : Active device 3
Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing)

(This is junk as it has no relationship to the actual array!) mdadm --examine /dev/md126
/dev/md126:
Version : 1.2
Raid Level : raid0
Total Devices : 4
Persistence : Superblock is persistent

State : inactive

Name : storagepc:raid-2tb
UUID : 73ea3bd2:50b609a1:768a7e19:ca3ef9f0
Events : 506196

Number Major Minor RaidDevice

- 8 0 - /dev/sda
- 8 16 - /dev/sdb
- 8 32 - /dev/sdc
- 8 48 - /dev/sdd

cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md125 : active (auto-read-only) raid5 sdp[5] sdh[1] sdf[4] sdg[2]

      2197720128 blocks super 1.2 level 5, 64k chunk, algorithm 2 [4/4]

[UUUU]

md126 : inactive sdc[6](S) sda[5](S) sdb[0](S) sdd[4](S)

      7814054240 blocks super 1.2

md127 : active (auto-read-only) raid5 sdj[2] sdn[4] sdm[1] sdl[5]

      2930284224 blocks super 1.2 level 5, 64k chunk, algorithm 2 [4/4]

[UUUU]

unused devices: <none>