Bug#405919: mdadm: checkarray does not report or fix mismatch_cnt issues

[Michel Lespinasse]

Package: mdadm
Version: 2.5.6-7
Severity: normal



My RAID1 arrays get checked by checkarray the first sunday of every 
month (default mdadm configuration, I think).

I have noticed that /sys/block/md1/md/mismatch_cnt reports a count of 
128 unsynchronized blocks. checkarray does not report or fix this issue.
Doing the same manually (echo check >/sys/block/md1/md/sync_action) does
not fix the issue either - mismatch_cnt is reset to 0 at the start of 
the resync, and goes up to 128 somewhere between 40% and 50% of the 
resync.

I believe checkarray should be made to report this issue, as my 
understanding was that the point of checkarray was to help with 
unsynchronized arrays ???

smartctl -a does not report any issues on either devices the RAID1 is 
based on.

I just noticed today that mdadm.conf only lists 3 of my 5 RAID1 volumes,
I do not know why (I did not edit the file after it was auto-generated).


-- Package-specific info:
--- mount output
/dev/md0 on / type ext2 (rw,errors=remount-ro)
tmpfs on /lib/init/rw type tmpfs (rw,nosuid,mode=0755)
proc on /proc type proc (rw,noexec,nosuid,nodev)
sysfs on /sys type sysfs (rw,noexec,nosuid,nodev)
procbususb on /proc/bus/usb type usbfs (rw)
udev on /dev type tmpfs (rw,mode=0755)
tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev)
devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=620)
tmpfs on /tmp type tmpfs (rw)
tmpfs on /var/tmp type tmpfs (rw,size=1g)
/dev/md1 on /home type ext2 (rw,nosuid,nodev,errors=remount-ro)
/dev/md3 on /mnt/extra0 type ext2 (rw,noexec,nosuid,nodev,errors=remount-ro)
/dev/md4 on /mnt/extra1 type ext2 (rw,noexec,nosuid,nodev,errors=remount-ro)
automount(pid1430) on /mnt/autofs type autofs (rw,fd=4,pgrp=1430,minproto=2,maxproto=4)

--- mdadm.conf
# Autogenerated by mdcfg. See mdadm.conf(5) for more details on this file.
DEVICE partitions
ARRAY /dev/md0 level=raid1 num-devices=2 devices=/dev/hde1,/dev/hdg1
   UUID=436d1e33:5613bb60:73401891:847eb5d1
ARRAY /dev/md1 level=raid1 num-devices=2 devices=/dev/hde2,/dev/hdg2
   UUID=096310d2:3269c085:7757eec1:62d16352
ARRAY /dev/md2 level=raid1 num-devices=2 devices=/dev/hde3,/dev/hdg3
   UUID=0b80a931:d5aa8c2c:bd233b49:f4b6d4ab
MAILADDR root

--- /proc/mdstat:
Personalities : [raid1] 
md4 : active raid1 hde3[1] hdc2[0]
      9783488 blocks [2/2] [UU]
      
md1 : active raid1 hdg2[1] hde2[0]
      126953536 blocks [2/2] [UU]
      [===========>.........]  resync = 56.0% (71133440/126953536) finish=27.1min speed=34242K/sec
      
md3 : active raid1 hdg3[1] hdc1[0]
      48827904 blocks [2/2] [UU]
      
md2 : active raid1 hdg4[1] hde4[0]
      1975104 blocks [2/2] [UU]
      
md0 : active raid1 hdg1[1] hde1[0]
      17574976 blocks [2/2] [UU]
      
unused devices: <none>

--- /proc/partitions:
major minor  #blocks  name

  22     0   58615704 hdc
  22     1   48827992 hdc1
  22     2    9787680 hdc2
  33     0  156290904 hde
  33     1   17575078 hde1
  33     2  126953662 hde2
  33     3    9783585 hde3
  33     4    1975995 hde4
  34     0  195360984 hdg
  34     1   17575078 hdg1
  34     2  126953662 hdg2
  34     3   48853665 hdg3
  34     4    1975995 hdg4
   9     0   17574976 md0
   9     2    1975104 md2
   9     3   48827904 md3
   9     1  126953536 md1
   9     4    9783488 md4

--- initrd.img-2.6.16.36:

--- /proc/modules:

-- System Information:
Debian Release: 4.0
  APT prefers testing
  APT policy: (500, 'testing'), (50, 'unstable')
Architecture: i386 (i686)
Shell:  /bin/sh linked to /bin/bash
Kernel: Linux 2.6.16.36
Locale: LANG=C, LC_CTYPE=C (charmap=ANSI_X3.4-1968)

Versions of packages mdadm depends on:
ii  debconf [debconf-2.0]        1.5.11      Debian configuration management sy
ii  libc6                        2.3.6.ds1-8 GNU C Library: Shared libraries
ii  lsb-base                     3.1-22      Linux Standard Base 3.1 init scrip
ii  makedev                      2.3.1-83    creates device files in /dev

Versions of packages mdadm recommends:
ii  module-init-tools             3.3-pre3-1 tools for managing Linux kernel mo
ii  postfix [mail-transport-agent 2.3.4-3    A high-performance mail transport 

-- debconf information:
* mdadm/autostart: true
* mdadm/initrdstart: /dev/md0
  mdadm/initrdstart_notinconf: false
  mdadm/initrdstart_msg_errexist:
  mdadm/initrdstart_msg_intro:
  mdadm/initrdstart_msg_errblock:
* mdadm/warning:
* mdadm/start_daemon: true
* mdadm/mail_to: root
  mdadm/initrdstart_msg_errmd:
  mdadm/initrdstart_msg_errconf:
* mdadm/autocheck: true