Re: Performance with 2 AMD/Opteron 2.6Ghz and 8gig - Mailing list pgsql-performance

I too have a DL385 with a single DC Opteron 270.
It claims to have a smart array 6i controller and over the last
couple of days I've been runnign some tests on it, which have been
yielding some suprising results.

I've got 6 10k U320 disks in it. 2 are in a mirror set.  We'll not
pay any attention to them.
The remaining 4 disks I've been toying with to see what config works
best, using hardware raid and software raid.

system info:
dl dl385 - 1 opteron 270 - 5GB ram - smart array 6i
cciss0: HP Smart Array 6i Controller
Firmware Version: 2.58
Linux db03 2.6.17-1.2157_FC5 #1 SMP Tue Jul 11 22:53:56 EDT 2006
x86_64 x86_64 x86_64 GNU/Linux
using xfs

Each drive can sustain 80MB/sec read (dd, straight off device)

So here are the results I have so far.  (averaged)


hardware raid 5:
dd - write 20GB file - 48MB/sec
dd - read 20GB file - 247MB/sec
[ didn't do a bonnie run on this yet ]
pretty terrible write performance. good read.

hardware raid 10
dd - write 20GB - 104MB/sec
dd - read 20GB - 196MB/sec
bonnie++
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
db03          9592M 45830  97 129501  31 62981  14 48524  99 185818
19 949.0   1

software raid 5
dd - write 20gb - 85MB/sec
dd - read 20gb - 135MB/sec

I was very suprised at those results. I was sort of expecting it to
smoke the hardware. I repeated the test many times, and kept getting
these numbers.

bonnie++:
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
db03          9592M 44110  97 81481  23 34604  10 44495  95 157063
28 919.3   1

software 10:
dd - write - 20GB - 108MB/sec
dd - read - 20GB - 86MB/sec(!!!! WTF? - this is repeatable!!)
bonnie++
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
db03          9592M 44539  98 105444  20 34127   8 39830  83 100374
10  1072   1


so I'm going to be going with hw r5, which went against what I
thought going in - read perf is more important for my usage than write.

I'm still not sure about that software 10 read number. something is
not right there...

--
Jeff Trout <jeff@jefftrout.com>
http://www.dellsmartexitin.com/
http://www.stuarthamm.net/