Very Poor Raid Card Performance - Solved
Steven Lowry
steve at midden.org
Wed Jan 17 11:06:01 UTC 2007
Problem solved, I believe.
Here is the results from Bonnie++ with the raid card set to "writethru"
which writes
directly to disk.
Version 1.93c ------Sequential Output------ --Sequential Input-
--Random-
-Per Chr- --Block-- -Rewrite- -Per Chr- --Block--
--Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP
/sec %CP
Mort 2G 322 99 17482 4 20280 7 683 99 581645 99
2261 65
Latency 25812us 260ms 1049ms 137ms 627us 100ms
I then set the card to "writeback" and got this.
Version 1.93c ------Sequential Output------ --Sequential Input-
--Random-
-Per Chr- --Block-- -Rewrite- -Per Chr- --Block--
--Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP
/sec %CP
Mort 2G 318 98 100299 37 96431 41 676 99 414514 99
9853 425
Latency 79085us 250ms 263ms 127ms 651us 97392us
Looks like write caching was not enabled, don't know why it worked in
windows XP though.
Thankfully I have a good UPS, wouldn't want to lose data because of a
power loss.
A big thanks to everyone for your advice.
Steve...
--
Folding at home http://folding.stanford.edu/
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