From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Falgout Subject: mismatch_cnt and Raid6 Date: Thu, 21 Apr 2011 08:00:39 -0500 Message-ID: <4DB02A77.8000902@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids I got an error last week from a new raid6 array about a mismatch_cnt. I did some reading online, performed a repair action on the array, performed a check action, and checked for the mismatch_cnt again. The number was greatly reduced, but it was still there. According to mdadm, everything appears to be working fine. All the drives are passing short tests on smartctl. What is mismatch_cnt really? Should I even be concerned about this? The array is giving me 25-30MB/sec performance on an sshfs mount over the network. With a local copy I can see speeds of 50 to 60MB/sec. Thanks, Andrew Falgout -----> inserting boring details here <----------- ==> checked for mismatch_cnt cat /sys/block/md1/md/mismatch_cnt 7752 ==> performed the repair this way: echo "repair" >/sys/block/md1/md/sync_action ==> performed the check this way: echo "check" >/sys/block/md1/md/sync_action ==> Array Details Array Details as follows: /dev/md1: Version : 1.2 Creation Time : Fri Mar 25 20:16:33 2011 Raid Level : raid6 Array Size : 7814047744 (7452.06 GiB 8001.58 GB) Used Dev Size : 1953511936 (1863.01 GiB 2000.40 GB) Raid Devices : 6 Total Devices : 6 Persistence : Superblock is persistent Intent Bitmap : Internal Update Time : Thu Apr 21 07:35:08 2011 State : active Active Devices : 6 Working Devices : 6 Failed Devices : 0 Spare Devices : 0 Layout : left-symmetric Chunk Size : 512K Name : nas.falgout.lan:1 (local to host nas.falgout.lan) UUID : df03c833:90129ffd:123abdca:6b30c319 Events : 75072 Number Major Minor RaidDevice State 0 8 1 0 active sync /dev/sda1 1 8 81 1 active sync /dev/sdf1 2 8 97 2 active sync /dev/sdg1 3 8 113 3 active sync /dev/sdh1 4 8 129 4 active sync /dev/sdi1 5 8 145 5 active sync /dev/sdj1 Disk Details: /dev/sda1: Magic : a92b4efc Version : 1.2 Feature Map : 0x1 Array UUID : df03c833:90129ffd:123abdca:6b30c319 Name : nas.falgout.lan:1 (local to host nas.falgout.lan) Creation Time : Fri Mar 25 20:16:33 2011 Raid Level : raid6 Raid Devices : 6 Avail Dev Size : 3907025072 (1863.01 GiB 2000.40 GB) Array Size : 15628095488 (7452.06 GiB 8001.58 GB) Used Dev Size : 3907023872 (1863.01 GiB 2000.40 GB) Data Offset : 2048 sectors Super Offset : 8 sectors State : clean Device UUID : 6735ec05:80890fa1:86e03b80:1f5de847 Internal Bitmap : 8 sectors from superblock Update Time : Thu Apr 21 07:45:17 2011 Checksum : 99fdeb3f - correct Events : 75072 Layout : left-symmetric Chunk Size : 512K Device Role : Active device 0 Array State : AAAAAA ('A' == active, '.' == missing) /dev/sdf1: Magic : a92b4efc Version : 1.2 Feature Map : 0x1 Array UUID : df03c833:90129ffd:123abdca:6b30c319 Name : nas.falgout.lan:1 (local to host nas.falgout.lan) Creation Time : Fri Mar 25 20:16:33 2011 Raid Level : raid6 Raid Devices : 6 Avail Dev Size : 3907025072 (1863.01 GiB 2000.40 GB) Array Size : 15628095488 (7452.06 GiB 8001.58 GB) Used Dev Size : 3907023872 (1863.01 GiB 2000.40 GB) Data Offset : 2048 sectors Super Offset : 8 sectors State : clean Device UUID : e18ce851:efc426b3:cadca5f9:df898fa7 Internal Bitmap : 8 sectors from superblock Update Time : Thu Apr 21 07:45:17 2011 Checksum : d122a72e - correct Events : 75072 Layout : left-symmetric Chunk Size : 512K Device Role : Active device 1 Array State : AAAAAA ('A' == active, '.' == missing) /dev/sdg1: Magic : a92b4efc Version : 1.2 Feature Map : 0x1 Array UUID : df03c833:90129ffd:123abdca:6b30c319 Name : nas.falgout.lan:1 (local to host nas.falgout.lan) Creation Time : Fri Mar 25 20:16:33 2011 Raid Level : raid6 Raid Devices : 6 Avail Dev Size : 3907025072 (1863.01 GiB 2000.40 GB) Array Size : 15628095488 (7452.06 GiB 8001.58 GB) Used Dev Size : 3907023872 (1863.01 GiB 2000.40 GB) Data Offset : 2048 sectors Super Offset : 8 sectors State : clean Device UUID : 4cff4ab7:8e7c4312:1445828a:f0be7e89 Internal Bitmap : 8 sectors from superblock Update Time : Thu Apr 21 07:45:17 2011 Checksum : 86d6e94 - correct Events : 75072 Layout : left-symmetric Chunk Size : 512K Device Role : Active device 2 Array State : AAAAAA ('A' == active, '.' == missing) /dev/sdh1: Magic : a92b4efc Version : 1.2 Feature Map : 0x1 Array UUID : df03c833:90129ffd:123abdca:6b30c319 Name : nas.falgout.lan:1 (local to host nas.falgout.lan) Creation Time : Fri Mar 25 20:16:33 2011 Raid Level : raid6 Raid Devices : 6 Avail Dev Size : 3907025072 (1863.01 GiB 2000.40 GB) Array Size : 15628095488 (7452.06 GiB 8001.58 GB) Used Dev Size : 3907023872 (1863.01 GiB 2000.40 GB) Data Offset : 2048 sectors Super Offset : 8 sectors State : clean Device UUID : 05a949c4:ab94a3f4:ae25fe55:8034dbfb Internal Bitmap : 8 sectors from superblock Update Time : Thu Apr 21 07:45:17 2011 Checksum : 35a48696 - correct Events : 75072 Layout : left-symmetric Chunk Size : 512K Device Role : Active device 3 Array State : AAAAAA ('A' == active, '.' == missing) /dev/sdi1: Magic : a92b4efc Version : 1.2 Feature Map : 0x1 Array UUID : df03c833:90129ffd:123abdca:6b30c319 Name : nas.falgout.lan:1 (local to host nas.falgout.lan) Creation Time : Fri Mar 25 20:16:33 2011 Raid Level : raid6 Raid Devices : 6 Avail Dev Size : 3907025072 (1863.01 GiB 2000.40 GB) Array Size : 15628095488 (7452.06 GiB 8001.58 GB) Used Dev Size : 3907023872 (1863.01 GiB 2000.40 GB) Data Offset : 2048 sectors Super Offset : 8 sectors State : clean Device UUID : ff0881e7:7e22804f:d0b57eb7:60872ff0 Internal Bitmap : 8 sectors from superblock Update Time : Thu Apr 21 07:45:17 2011 Checksum : 98d5766 - correct Events : 75072 Layout : left-symmetric Chunk Size : 512K Device Role : Active device 4 Array State : AAAAAA ('A' == active, '.' == missing) /dev/sdj1: Magic : a92b4efc Version : 1.2 Feature Map : 0x1 Array UUID : df03c833:90129ffd:123abdca:6b30c319 Name : nas.falgout.lan:1 (local to host nas.falgout.lan) Creation Time : Fri Mar 25 20:16:33 2011 Raid Level : raid6 Raid Devices : 6 Avail Dev Size : 3907025072 (1863.01 GiB 2000.40 GB) Array Size : 15628095488 (7452.06 GiB 8001.58 GB) Used Dev Size : 3907023872 (1863.01 GiB 2000.40 GB) Data Offset : 2048 sectors Super Offset : 8 sectors State : clean Device UUID : 9a200b64:483f52d0:a3d97d13:39ff95be Internal Bitmap : 8 sectors from superblock Update Time : Thu Apr 21 07:45:17 2011 Checksum : 314f2777 - correct Events : 75072 Layout : left-symmetric Chunk Size : 512K Device Role : Active device 5 Array State : AAAAAA ('A' == active, '.' == missing)