Ingo Molnar wrote:
>
> could you send me your /etc/raidtab? I've tested the performance of 4-disk
> RAID0 on SCSI, and it scales perfectly here, as far as hdparm -t goes.
> (could you also send the 'hdparm -t /dev/md0' results, do you see a
> degradation in those numbers as well?)
>
> it could either be some special thing in your setup, or an IDE+RAID
> performance problem.
>
> Ingo
It think it might be an IDE bottleneck.
if i use dd to read 800MB from each of my drives individually the speeds
i get are
hde=22MB/s
hdg=22MB/s
hdi=18MB/s
hdk=20MB/s
if i do the same tests simultaneously i get 10MB/s from each of the four
drives
if i do the same test on just hde hdg and hdk i get 13MB/s from each of
three drives
if i do it on hde and hdg i get 18MB/s from each. (both ide channels on
one card
On hdi and hdk i get 15MB/s
I conclude that on my system there is an ide saturation point (or
bottleneck) around 40MB/s
But the same thing happens under 2.2, so it doesnt explain the
performance difference between 2.2 and 2.[34], so there must be another
bottleneck somewhere as well.... back to the drawing board i guess.
Glenn
