Brian Pomerantz wrote:
>
> On Wed, Mar 08, 2000 at 06:52:52PM -0000, Matthew Clark wrote:
> > Hmm.. well you may think 26Mb/Sec is poor for writing.. I would be drooling
> > at such vast speeds..
> >
> > Would you mind telling me how you set up your raid array (i.e. policies) and
> > filesystem (inodes, block sizes, strides etc)...I'm seeing 2M/b per sec on
> > writes and only 16-17mb/sec on reads.. sequential or random!!!
> >
>
> I believe for the 26MB/s across two chains I set up the Mylex board to
> have 64KB stripe and 64KB segment size. For ext2, I modified it to
> use 8KB block size (which is the page size on Alpha, Ted says that
> won't work on Intel). So I called mke2fs like this:
>
> mke2fs -b 8192 -R stride=8 -i 16384 -s 1 /dev/rd/c0d0p1
>
> I also use write-back, which increased the performance a bit.
I've done a little testing with the Mylex 1164 to establish a
baseline. These comments are based on bonnie sequential numbers.
I am not using as many drives as Brian, so I am not controller
limited.
RAID5: Writeback improvement vs. Writethru delta is about 33%
for a 32MB cache.
Segment size of 8K improvement vs. 64K is about 10%
The slight improvement that results from reducing the segment size
in the Mylex controller indicates to me that there remains a lot
of room for tuning in linux for sequential transfers.
--
Dan Jones, Storage Engineer VA Linux Systems
V:(408)542-5737 F:(408)745-9130 1382 Bordeaux Drive
[EMAIL PROTECTED] Sunnyvale, CA 94089
