On Aug 22, 2006, at 2:17 AM, Robert Urban wrote:
Hi Folks,
using a simple test program to write sequential blocks to a file,
optionally
opening with O_SYNC, I've tested write performance to a MegaRAID
logical
drive consisting of a RAID-5 set of 4 72GB HP Ultra320 disks and to
a RAID-0
drive consisting of a single 300GB HP Ultra320 disk. The controller
has 128MB of cache, but I do not have a battery, so cache write policy
is write-through. The kernel is the "bsd", and not "bsd.mp", but
it makes
no difference. I've tried both.
Had the same kind of low performance on a Dell server with an entry
level RAID adapter.
I took the risk to force cache write policy to write-back, even
without a battery.
Performance is as it should be for a RAID-0, I'm just sweating a bit
more...
Next time, will add a few bucks and buy a real controller.
Regards.
