On Feb 13, 2008, at 12:06, Dave Cramer wrote:
On 13-Feb-08, at 5:02 AM, Tore Halset wrote:
Hello.
I think I started that discussion. We ended up buying a Dell 2900
with PERC 6/i and 10 * 145GB SAS 3,5" 15KRpm discs. 6 of the SAS
discs are in a raid 10 for the database, 2 in a mirror for the wal
and the last 2 in a mirror for the OS. We get 350MB/s writing and
380MB/s reading to/from the raid 10 area using dd. The OS is Ubuntu
and the filesystem for the raid 10 is ext3.
Wow that's fantastic. Just to be sure, did you make sure that you
read and wrote 2x memory to take the cache out of the measurement ?
Dave
The box have 16GB of ram, but my original test file was only 25GB.
Sorry. Going to 33GB lowered the numbers for writing. Here you have
some samples.
% sh -c "dd if=/dev/zero of=bigfile bs=8k count=4000000 && sync"
32768000000 bytes (33 GB) copied, 103.722 seconds, 316 MB/s
32768000000 bytes (33 GB) copied, 99.669 seconds, 329 MB/s
% time dd if=bigfile of=/dev/null bs=8k
32768000000 bytes (33 GB) copied, 85.4235 seconds, 384 MB/s
32768000000 bytes (33 GB) copied, 85.4628 seconds, 383 MB/s
Regards,
- Tore.
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