[ Tuesday, January 11, 2000 ] [EMAIL PROTECTED] wrote:
> >what stripe/chunk sizes are you using in the raid? My exp. has been
> >smaller is better down to 4k, although I'm not sure why :)
>
> We're currently using 8k but with our load then if I can go smaller
> I will do.
> Is there any merit in using -R on mke2fs if we're doing raid1?
I've always interpreted -R stride= as meaning "how many ext2 blocks to
gather before sending to the lower-level block device". This way the
block device can deal with things more efficiently. Since the stride=
must default to 1 (I can't see how it could pick a different one) then
any time your device (h/w or s/w raid) is using larger block sizes -R
would seem to be a good choice (for 8K block sizes, stride=2)
The raid1 shouldn't matter as much, so try without stride= and then with
stride=2 (if still using 8K block sizes)
I get the feeling that the parallelism vs. efficiency tradeoff in block
sizes still isn't fully understood, but lots of random writes should
almost certainly do best with the smallest block sizes available down
to a single page (4k)
As always, I'd like to solicit other views on this :)
James
--
Miscellaneous Engineer --- IBM Netfinity Performance Development
