Re: possible bug - bitmap dirty pages status

On Sat, Aug 27, 2011 at 1:58 PM, CoolCold [off-list ref] wrote:

Hello!
I have raid1 array with bitmap (md3), one disk has died, been replaced
and array resynced:

Aug 25 15:38:03 gamma2 kernel: [    5.986791] md: md3 stopped.
Aug 25 15:38:03 gamma2 kernel: [    6.043306] raid1: raid set md3
active with 1 out of 2 mirrors
Aug 25 15:38:03 gamma2 kernel: [    6.044378] md3: bitmap initialized
from disk: read 2/2 pages, set 357 bits
Aug 25 15:38:03 gamma2 kernel: [    6.044442] created bitmap (22
pages) for device md3
Aug 25 15:38:03 gamma2 kernel: [    6.070492] md3: detected capacity
change from 0 to 1478197903360
Aug 25 15:38:03 gamma2 kernel: [    6.070862]  md3: unknown partition table
Aug 26 19:33:33 gamma2 kernel: [100325.814179] md: md3: recovery done.

Now, /proc/mdstats still shows "dirty" bitmap, 16 of 22 pages:

root@gamma2:~# cat /proc/mdstat
Personalities : [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md3 : active raid1 sdc3[1] sdb3[0]
     1443552640 blocks [2/2] [UU]
     bitmap: 16/22 pages [64KB], 32768KB chunk

root@gamma2:~# mdadm -D /dev/md3
/dev/md3:
       Version : 00.90
 Creation Time : Wed Oct 13 03:13:52 2010
    Raid Level : raid1
    Array Size : 1443552640 (1376.68 GiB 1478.20 GB)
 Used Dev Size : 1443552640 (1376.68 GiB 1478.20 GB)
  Raid Devices : 2
 Total Devices : 2
Preferred Minor : 3
   Persistence : Superblock is persistent

 Intent Bitmap : Internal

   Update Time : Sat Aug 27 13:53:57 2011
         State : active
 Active Devices : 2
Working Devices : 2
 Failed Devices : 0
 Spare Devices : 0

          UUID : f5a9c1da:83dd4c40:d363f6aa:3cbcebe5
        Events : 0.1381014

   Number   Major   Minor   RaidDevice State
      0       8       19        0      active sync   /dev/sdb3
      1       8       35        1      active sync   /dev/sdc3



That is strange as I can understand.

distrib & mdadm info:
Debian Lenny with openvz kernel from lenny-backports.

root@gamma2:~# cat /proc/version
Linux version 2.6.32-bpo.5-openvz-amd64 (Debian 2.6.32-35~bpo50+1)
(norbert@tretkowski.de) (gcc version 4.3.2 (Debian 4.3.2-1.1) ) #1 SMP
Wed Jul 20 11:23:01 UTC 2011
root@gamma2:~# mdadm --version
mdadm - v2.6.7.2 - 14th November 2008

More details now:
Array still has 16/22 dirty pages:

root@gamma2:~# date;cat /proc/mdstat |head -n 5
Wed Aug 31 13:04:26 MSD 2011
Personalities : [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md3 : active raid1 sdc3[1] sdb3[0]
      1443552640 blocks [2/2] [UU]
      bitmap: 16/22 pages [64KB], 32768KB chunk


bitmap info:

root@gamma2:~# mdadm --examine-bitmap /dev/sdb3
        Filename : /dev/sdb3
           Magic : 6d746962
         Version : 4
            UUID : f5a9c1da:83dd4c40:d363f6aa:3cbcebe5
          Events : 1381014
  Events Cleared : 1381014
           State : OK
       Chunksize : 32 MB
          Daemon : 5s flush period
      Write Mode : Normal
       Sync Size : 1443552640 (1376.68 GiB 1478.20 GB)
          Bitmap : 44054 bits (chunks), 189 dirty (0.4%)
root@gamma2:~# mdadm --examine-bitmap /dev/sdc3
        Filename : /dev/sdc3
           Magic : 6d746962
         Version : 4
            UUID : f5a9c1da:83dd4c40:d363f6aa:3cbcebe5
          Events : 1381014
  Events Cleared : 1381014
           State : OK
       Chunksize : 32 MB
          Daemon : 5s flush period
      Write Mode : Normal
       Sync Size : 1443552640 (1376.68 GiB 1478.20 GB)
          Bitmap : 44054 bits (chunks), 189 dirty (0.4%)

--
Best regards,
[COOLCOLD-RIPN]

-- 
Best regards,
[COOLCOLD-RIPN]
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