On 18.07.2007 13:19, Justin Piszcz wrote:
For the HW RAID tests (2) at the bottom of the e-mail, no, I did not set
nr_requests or use the deadline scheduler.
For the SW RAID tests, I applied similar optimizations, I am probably
not at the latest firmware. The main thing I wanted to use though was
SW RAID because the card itself offers so many ports, however, with
write speed being that slow I am not sure its a good idea.
I think what you might be experiencing is that XFS can read su,sw values
from the MD device and will automatically optimize itself, while it
can't do that for the HW RAID device. It is absolutely essential to
align your file system, to prevent implicit reads, needed for parity
calculations.
Set su to the stripe size you have configured in your controller (like
128K) and sw to 9 (for a 10 disk RAID 5 array).
--
Regards,
Hannes Dorbath
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