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#1 2013-01-10 17:53:01

fabertawe
Member
From: Lloegr
Registered: 2009-11-24
Posts: 257

[SOLVED] RAID1 unexpected md0_resync

Hi Folks,

I've been running a 1TB RAID1 array for a good few months without issue and have never seen the mdo_resync and md0_raid1 processes running before. Does this indicate a problem and if so, how can I diagnose it?

I'd previously booted with a kernel panic. I then rebooted and fsck'd all my drives, rebooted again and here we are.

Personalities : [raid1] 
md0 : active raid1 sda1[0] sdd1[1]
      974430016 blocks super 1.2 [2/2] [UU]
      [=====>...............]  resync = 28.2% (275412416/974430016) finish=107.1min speed=108684K/sec
      
unused devices: <none>

/dev/md0:
        Version : 1.2
  Creation Time : Tue Oct 16 12:36:41 2012
     Raid Level : raid1
     Array Size : 974430016 (929.29 GiB 997.82 GB)
  Used Dev Size : 974430016 (929.29 GiB 997.82 GB)
   Raid Devices : 2
  Total Devices : 2
    Persistence : Superblock is persistent

    Update Time : Thu Jan 10 17:43:15 2013
          State : active, resyncing 
 Active Devices : 2
Working Devices : 2
 Failed Devices : 0
  Spare Devices : 0

  Resync Status : 28% complete

           Name : arch64:0  (local to host arch64)
           UUID : 0930e707:614de0a3:3f4f73ee:a04f940f
         Events : 250

    Number   Major   Minor   RaidDevice State
       0       8        1        0      active sync   /dev/sda1
       1       8       49        1      active sync   /dev/sdd1

/dev/sda1:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x0
     Array UUID : 0930e707:614de0a3:3f4f73ee:a04f940f
           Name : arch64:0  (local to host arch64)
  Creation Time : Tue Oct 16 12:36:41 2012
     Raid Level : raid1
   Raid Devices : 2

 Avail Dev Size : 1948860416 (929.29 GiB 997.82 GB)
     Array Size : 974430016 (929.29 GiB 997.82 GB)
  Used Dev Size : 1948860032 (929.29 GiB 997.82 GB)
    Data Offset : 262144 sectors
   Super Offset : 8 sectors
          State : active
    Device UUID : 5f7bd68e:c7f4fa8c:726e9cb0:e2f4686e

    Update Time : Thu Jan 10 17:43:15 2013
       Checksum : aff3a99f - correct
         Events : 250


   Device Role : Active device 0
   Array State : AA ('A' == active, '.' == missing)

/dev/sdd1:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x0
     Array UUID : 0930e707:614de0a3:3f4f73ee:a04f940f
           Name : arch64:0  (local to host arch64)
  Creation Time : Tue Oct 16 12:36:41 2012
     Raid Level : raid1
   Raid Devices : 2

 Avail Dev Size : 1948860416 (929.29 GiB 997.82 GB)
     Array Size : 974430016 (929.29 GiB 997.82 GB)
  Used Dev Size : 1948860032 (929.29 GiB 997.82 GB)
    Data Offset : 262144 sectors
   Super Offset : 8 sectors
          State : active
    Device UUID : 3bb7c5cf:2f34c77e:c45ffedf:74c8c5ee

    Update Time : Thu Jan 10 17:43:15 2013
       Checksum : 926de9c9 - correct
         Events : 250


   Device Role : Active device 1
   Array State : AA ('A' == active, '.' == missing)

Please advise!

Last edited by fabertawe (2013-01-10 20:02:36)


i7 4790K 4.4GHz, ASRock Z97 Extreme6, 16GB 2400MHz, GTX 970, Arch x86_64

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#2 2013-01-10 19:10:24

65kid
Member
From: Germany
Registered: 2011-01-26
Posts: 663

Re: [SOLVED] RAID1 unexpected md0_resync

resync != rebuild

I wondered about the same thing once after I had to do a hard reset. resync just checks if the RAID data is still consistent, so it's basically a "RAID fsck". wink
In other words, usually nothing to worry about... wink

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#3 2013-01-10 19:36:53

fabertawe
Member
From: Lloegr
Registered: 2009-11-24
Posts: 257

Re: [SOLVED] RAID1 unexpected md0_resync

Thanks 65kid.

So what's triggering this resync? I can't find anything under /etc/cron* or /etc/systemd.

Edit: Is this applicable?

Jan 10 17:01:48 arch64 systemd[1]: Unmounting /media/Array...
Jan 10 17:01:48 arch64 umount[1078]: umount: /media/Array: target is busy.
Jan 10 17:01:48 arch64 umount[1078]: (In some cases useful info about processes that use
Jan 10 17:01:48 arch64 umount[1078]: the device is found by lsof(8) or fuser(1))
Jan 10 17:01:48 arch64 systemd[1]: media-Array.mount mount process exited, code=exited status=32
Jan 10 17:01:48 arch64 systemd[1]: Failed unmounting /media/Array.
...
Jan 10 17:01:48 arch64 systemd[1]: Unit media-Array.mount entered failed state

Last edited by fabertawe (2013-01-10 19:43:41)


i7 4790K 4.4GHz, ASRock Z97 Extreme6, 16GB 2400MHz, GTX 970, Arch x86_64

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#4 2013-01-10 19:46:34

65kid
Member
From: Germany
Registered: 2011-01-26
Posts: 663

Re: [SOLVED] RAID1 unexpected md0_resync

You said it yourself, you had a kernel panic, so the RAID was not cleanly shut down. This forces a resync on the next boot.

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#5 2013-01-10 19:54:23

fabertawe
Member
From: Lloegr
Registered: 2009-11-24
Posts: 257

Re: [SOLVED] RAID1 unexpected md0_resync

I'm positive I've had other unclean shutdowns whilst running this array and not seen this resyncing before. I'll take your word for it though, it does make sense.

I've not noticed this before but it seems I've been getting the "Failed unmounting /media/Array" mentioned previously at every shutdown!


i7 4790K 4.4GHz, ASRock Z97 Extreme6, 16GB 2400MHz, GTX 970, Arch x86_64

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