[ale] md0 tasks taking 60-80% of CPU

[JK]

Pat Regan wrote:

>JK wrote:
>  
>
>>Here they are. I'm guessing the "resync" state has something
>>to do with the CPU usage...
>>
>>--------------/proc/mdstat:---------------
>>
>>Personalities : [raid1]
>>md0 : active raid1 hda3[0] hdd3[1]
>>      155637632 blocks [2/2] [UU]
>>      [============>........]  resync = 63.2% (98368448/155637632) 
>>finish=352.7min speed=2703K/sec
>>md1 : active raid1 hda1[0] hdd1[1]
>>      128384 blocks [2/2] [UU]
>>    
>>
>
>You are only pushing 3 MB/sec and using 60-80% cpu.  This would lead me
>to believe that you don't have DMA enabled on the drives.
>
>This command should tell you if DMA is enabled:
>
>hdparm /dev/hda
>
>This one should enable it:
>
>hdparm -D 1 /dev/hda
>  
>
Woohoo! That did the trick!  After turning on DMA for both drives
(I guess Knoppix leaves it disabled for safety) it's now pushing 17MB/sec,
and will be done in half an hour. And the CPU is 98% idle.

(BTW, the appropriate option is "-d", not "-D".)

Thanks,

-- JK