Hi,
On Tue, Apr 11, 2000 at 12:29:32PM -0600, Anders Engle wrote:
> Does anyone have any experience with PowerEdge and the PERC2/SC
> controller? I've just recieved one from Dell, but it is sluggish.
> Our configuration is 2x700Mhz and 1G ram, but almost any disk activity
> will make the system VERY unresponsive. My Precision (also smp) is barely
> affected by the same test (just copying some directories).
> Does anybody have any sugestions, or do I take this badboy back to Dell?
The perc2/sc is a slow raid card but is to be preferred over most plain
(non-raid) scsi controllers, IMHO. I imagine its pessimal configuration
gives extremely poor performance, definitely worse than straight scsi
drives. Sounds to me like you've stumbled onto an only slightly sub-pessimal
configuration. :-)
How much cache has your 2/sc got? More cache is better. Lots more cache
is lots better. :-)
How have you configured the drives/array(s)? If you use a tiny chunk/stripe
size, performance won't be great, except under very specialized load.
Bigger /tends/ to be better, but ymmv.
Does your card have a battery backup unit and if so, have you set writeback?
This really improves performance. If you don't have a bbu, it's dangerous
to set writeback, but it's your call.
What version of the megaraid driver are you using? Don't know anything
about which are better, but it might be best to go for the latest.
When you created your filesystems, did you set the "stride" parameter?
If you create (say) a raid5 array with a 64kb thingy, then you can (IIRC)
get best performance by creating filesystems on that array like...
mke2fs -b 4096 -R stride=16 /dev/sdx1
Also, to get more than one logical drive recognised by linux, you have to
turn on "probe all LUNs". I think later versions of the kernel do this
for you if you select the megaraid driver.
All the best,
Wesley.
-
Linux SMP list: FIRST see FAQ at http://www.irisa.fr/prive/dmentre/smp-howto/
To Unsubscribe: send "unsubscribe linux-smp" to [EMAIL PROTECTED]
