[Tfug] Really slow mdadm resyncing

[Matt Jacob]

On 6/17/07, Harry McGregor <micros at osef.org> wrote:
> Hi Matt,
>
> It sounds like the drives are not in DMA mode.

You were right: one drive had DMA on and the other one had it off.
Turning DMA on solved my problems and the resync went from 1M/s to
30M/s. While I was at it, I did this to set both drives to use ATA100
(udma5):

hdparm -d1 -X69 /dev/hda
hdparm -d1 -X69 /dev/hdb

The default setting was using mdma2 (I think) or udma2 (ATA33). Eek.
This looks much better:

ned:~# hdparm -Tt /dev/hda

/dev/hda:
 Timing cached reads:   370 MB in  2.01 seconds = 184.41 MB/sec
 Timing buffered disk reads:  176 MB in  3.03 seconds =  58.06 MB/sec

Thanks to you and Robert for the help. I'll blame you guys if my
drives start a fire and torch the box.

Matt