[tech] martello speed
James Andrewartha
trs80 at ucc.gu.uwa.edu.au
Wed Mar 23 18:41:43 WST 2005
The new SATA controller has been installed in martello, and I've been
benchmarking various RAID configurations with bonnie++. The results are
somewhat interesting (commands used to set up each configuration included
in case I did something stupid):
RAID 5
------
mdadm -Cv -l5 -n4 -c128 /dev/md0 /dev/sx8/[0123]p1
(this only resynced at 22MB/s)
pvcreate /dev/md0
vgcreate reliable /dev/md0
lvcreate -L 40G -n home reliable
mke2fs -b 4096 -E stride=32 -j -m 1 -O dir_index -v /dev/mapper/reliable-home
bonnie++ -d bonnie++ -u trs80 -m martello
Version 1.03 ------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
martello 4G 38175 92 65903 27 20999 8 26989 60 58108 12 170.9 0
(fiddling with blockdev --setra didn't do much)
RAID 1+0
--------
mdadm -Cv -l1 -n2 /dev/md0 /dev/sx8/[01]p1
mdadm -Cv -l1 -n2 /dev/md1 /dev/sx8/[23]p1
(these would only resync at a total rate of 40MB/s, regardless of how whether
I stopped one array or not. Further, when only md0 was resyncing, an hdparm of
/dev/sx8/3p1 returned 30MB/s, compared to the normal 55MB/s)
pvcreate /dev/md0 /dev/md1
vgcreate reliable /dev/md0 /dev/md1
lvcreate -L 40G -i2 -I32 -n home reliable
mke2fs -b 4096 -E stride=8 -j -m 1 -O dir_index -v /dev/mapper/reliable-home
bonnie++ -d bonnie++ -u trs80 -m martello
Version 1.03 ------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
martello 4G 39478 97 66125 29 19881 5 29657 65 58542 8 199.8 0
Bare disk
---------
mke2fs -j -m 1 -O dir_index -v /dev/sx8/0p1
bonnie++ -d bonnie++ -u trs80 -m martello
Version 1.03 ------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
martello 4G 38044 93 57773 25 17714 6 27826 60 45065 5 215.6 0
The bare disk result bears out the hdparm value of 55MB/s. The question is,
where's the performance improvement that should happend for RAID 1+0 and
RAID 5? The slow resync and hdparm result during array construction says to
me that the ports on the controller are not independent.
A little searching finds
http://forums.storagereview.net/index.php?showtopic=17794&hl=promise which
claims "The linux driver sends only one command to the board at a time."
--
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# UCC Wheel Member http://trs80.ucc.asn.au/ #| what squirrels do best |
[ "There's nobody getting rich writing ]| -- Collect and hide your |
[ software that I know of" -- Bill Gates, 1980 ]\ nuts." -- Acid Reflux #231 /
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