Re: Linux 3.3.1 resync speed

[Larkin Lowrey <llowrey@xxxxxxxxxxxxxxxxx>]

This is a known issue and a patch has been submitted. I'm not sure when
it is scheduled to appear in the kernel.

There will be no actual disk I/O during the raid check and the array
will not actually be checked.

--Larkin

On 4/2/2012 4:21 PM, Mathias Burén wrote:
> Hi mailing list,
>
> On my old
>
> model name	: Intel(R) Atom(TM) CPU  330   @ 1.60GHz
>
> I'm currently seeing a resync speed of around 200MB/s!
>
> ~ $ cat /proc/mdstat
> Personalities : [raid6] [raid5] [raid4]
> md0 : active raid6 sdg1[0] sde1[7] sdh1[8] sdf1[5] sdc1[3] sdd1[4] sdb1[9]
>       9751756800 blocks super 1.2 level 6, 64k chunk, algorithm 2
> [7/7] [UUUUUUU]
>       [======>..............]  check = 32.6% (636923520/1950351360)
> finish=111.2min speed=196740K/sec
>
> unused devices: <none>
>
> This ia almost 10 times higher than what I used to see on 3.2 and
> earlier. What's that about? The array is a 7 drive RAID6:
>
> $ sudo mdadm -D /dev/md0
> /dev/md0:
>         Version : 1.2
>   Creation Time : Tue Oct 19 08:58:41 2010
>      Raid Level : raid6
>      Array Size : 9751756800 (9300.00 GiB 9985.80 GB)
>   Used Dev Size : 1950351360 (1860.00 GiB 1997.16 GB)
>    Raid Devices : 7
>   Total Devices : 7
>     Persistence : Superblock is persistent
>
>     Update Time : Mon Apr  2 22:18:14 2012
>           State : clean, checking
>  Active Devices : 7
> Working Devices : 7
>  Failed Devices : 0
>   Spare Devices : 0
>
>          Layout : left-symmetric
>      Chunk Size : 64K
>
>    Check Status : 32% complete
>
>            Name : ion:0  (local to host ion)
>            UUID : e6595c64:b3ae90b3:f01133ac:3f402d20
>          Events : 6773811
>
>     Number   Major   Minor   RaidDevice State
>        0       8       97        0      active sync   /dev/sdg1
>        9       8       17        1      active sync   /dev/sdb1
>        4       8       49        2      active sync   /dev/sdd1
>        3       8       33        3      active sync   /dev/sdc1
>        5       8       81        4      active sync   /dev/sdf1
>        8       8      113        5      active sync   /dev/sdh1
>        7       8       65        6      active sync   /dev/sde1
>
> Best regards,
> Mathias
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