Re: Linux 3.3.1 resync speed

[Mathias Burén <mathias.buren@xxxxxxxxx>]

On 2 April 2012 22:21, Mathias Burén <mathias.buren@xxxxxxxxx> 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

It was actually capped at 200000 KB/s in
/sys/block/md0/md/sync_speed_max . I raised that by a factor of 100,
and I am now seeing:

 $ 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 = 34.8% (679312336/1950351360)
finish=70.2min speed=301438K/sec

unused devices: <none>

I'm not complaining, just very surprised and I'm wondering if
everything is OK. Usually a check takes around 20-24 hours.

Mathias
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