Hello folks,
Due to too much coffee while diagnosing another problem... I found myself
unable to sleep. So I did some ide raid0 benchmarks for everyone to mull
over.
[Note that I did these benchmarks with hdparm and not bonnie, as I actually
had a readable raid5 filesystem on this disk set. But if I played around
with raidtab's and hdparm I could do some non-destructive benchmarking.
I am running redhat-6.0+updates, linux kernel 2.2.12, with
raid0145-19990824-2.2.11.gz and 2.2.12.uniform-ide-6.20.hydra.patch.gz. The
machine is an Abit-BP6, celeron 366, 128MB RAM. All of the disks tested are
Maxtor 90845D4 5400RPM disks, or a close relative. ide0-1 is an Intel
PIIX4, ide2-7 are three PDC20246 controllers.
All of these tests were conducted with one disk per channel except for hdb1
which is slave on the same channel as the boot disk (system was otherwise
idel)
First set of tests: RAID0, 4k chunk size, cpu clocked at 366Mhz.
All hdparms reported:
Timing buffer-cache reads: 128 MB in 1.67 seconds =76.65 MB/sec
2 disks (hdb1,hdc1) buffered disk reads : 24.24 MB/sec
3 disks (hdb1,hdc1,hde1) buffered disk : 31.37 MB/sec
4 disks (hdb1,hdc1,hde1,hdg1) bfr disk : 35.75 MB/sec
5 disks (hdb1,hdc1,hde1,hdg1,hdi1) disk : 31.68 MB/sec
6 disks (hdb1,hdc1,hde1,hdg1,hdi1,hdk1) : 32.82 MB/sec
7 disks (hdb,hdc,hde,hdg,hdi,hdk,hdm) : 31.84 MB/sec
8 disks (hdb,hdc,hde,hdg,hdi,hdk,hdm,hdo): 32.00 MB/sec
Same system. same disks, clocked at 550Mhz:
Timing buffer-cache reads: 128 MB in 1.07 seconds =119.63 MB/sec
2 disks (hdb1,hdc1) buffered disk reads : 24.81 MB/sec
3 disks (hdb1,hdc1,hde1) buffered disk : 31.84 MB/sec
4 disks (hdb1,hdc1,hde1,hdg1) bfr disk : 37.65 MB/sec
5 disks (hdb1,hdc1,hde1,hdg1,hdi1) disk : 37.87 MB/sec
6 disks (hdb1,hdc1,hde1,hdg1,hdi1,hdk1) : 35.96 MB/sec
7 disks (hdb,hdc,hde,hdg,hdi,hdk,hdm) : 35.16 MB/sec
8 disks (hdb,hdc,hde,hdg,hdi,hdk,hdm,hdo): 32.65 MB/sec
Bonus test, one disk from each controller, clocked at 550:
4 disks (hdc1,hde1,hdi1,hdm1) bfr disk : 38.79 MB/sec
Completely non-useful bonus test:
10 disk raid5 set, 2 channels contain both master and slave disks for the
set. 128k chunk size, 550Mhz, running in degraded mode.
Timing buffered disk reads: 64 MB in 3.73 seconds =17.16 MB/sec
Any comments or thoughts? I don't run raid0 in production, so this is no
bitch fest. But I was pretty deep into my raid setup, and I thought people
might appreciate some numbers. I was surprised to see the throughput top
out at four disks and then drop lower after that.
Tom
