Very slow raid5 resync
 

Trying to create a raid5 array with 4 1.5TB disks.
The resync is very slow. (mdstat shows about 1500K/sec).

I have tried raising the speed_limit_min but nothing changes.
I have also tried to benchmark the disk. They seems to be ok.

The resync also takes very much cpu. Why is is so slow?

Hi,

please check
/proc/sys/dev/raid/speed_limit_min and
/proc/sys/dev/raid/speed_limit_max

What do they say?

[root@nb2 ~]# cat /proc/sys/dev/raid/speed_limit_min
100000
[root@nb2 ~]# cat /proc/sys/dev/raid/speed_limit_max
200000

Solved!
 

I solved the problem by using a pci sata-controller instead of the onboard controller. Got the speed up to 27000Kb/sec.