On Mon, Mar 20, 2006 at 01:27:56PM -0800, Luke Lonergan wrote:
> >> Transfer rates:
> >> outside: 102400 kbytes in 2.075984 sec = 49326 kbytes/sec
> >> middle: 102400 kbytes in 2.100510 sec = 48750 kbytes/sec
> >> inside: 102400 kbytes in 2.042313 sec = 50139 kbytes/sec
> >>
> > I have 6 ultra a320 72G 10k discs
>
> Yah - ouch. With 6 drives in a RAID10, you should expect 3 drives worth of
> sequential scan performance, or anywhere from 100MB/s to 180MB/s. You're
> getting from half to 1/3 of the performance you'd get with a decent raid
> controller.
>
> If you add a simple SCSI adapter like the common LSI U320 adapter to your
> DL380G3 and then run software RAID, you will get more than 150MB/s with less
> CPU consumption. I'd also expect you'd get down to about 2ms access times.
FWIW, here's my dirt-simple workstation, with 2 segate SATA drives setup
as a mirror using software (first the mirror, then one of the raw
drives):
decibel@xxxxxx[5:43]~:15>sudo diskinfo -vt /dev/mirror/gm0
Password:
/dev/mirror/gm0
512 # sectorsize
300069051904 # mediasize in bytes (279G)
586072367 # mediasize in sectors
Seek times:
Full stroke: 250 iter in 1.416409 sec = 5.666 msec
Half stroke: 250 iter in 1.404503 sec = 5.618 msec
Quarter stroke: 500 iter in 2.887344 sec = 5.775 msec
Short forward: 400 iter in 2.101949 sec = 5.255 msec
Short backward: 400 iter in 2.373578 sec = 5.934 msec
Seq outer: 2048 iter in 0.209539 sec = 0.102 msec
Seq inner: 2048 iter in 0.347499 sec = 0.170 msec
Transfer rates:
outside: 102400 kbytes in 3.183924 sec = 32162 kbytes/sec
middle: 102400 kbytes in 3.216232 sec = 31838 kbytes/sec
inside: 102400 kbytes in 4.242779 sec = 24135 kbytes/sec
decibel@xxxxxx[5:43]~:16>sudo diskinfo -vt /dev/ad4
/dev/ad4
512 # sectorsize
300069052416 # mediasize in bytes (279G)
586072368 # mediasize in sectors
581421 # Cylinders according to firmware.
16 # Heads according to firmware.
63 # Sectors according to firmware.
Seek times:
Full stroke: 250 iter in 5.835744 sec = 23.343 msec
Half stroke: 250 iter in 4.364424 sec = 17.458 msec
Quarter stroke: 500 iter in 6.981597 sec = 13.963 msec
Short forward: 400 iter in 2.157210 sec = 5.393 msec
Short backward: 400 iter in 2.330445 sec = 5.826 msec
Seq outer: 2048 iter in 0.181176 sec = 0.088 msec
Seq inner: 2048 iter in 0.198974 sec = 0.097 msec
Transfer rates:
outside: 102400 kbytes in 1.715810 sec = 59680 kbytes/sec
middle: 102400 kbytes in 1.937027 sec = 52865 kbytes/sec
inside: 102400 kbytes in 3.260515 sec = 31406 kbytes/sec
No, I don't know why the transfer rates for the mirror are 1/2 that as the raw
device. :(
--
Jim C. Nasby, Sr. Engineering Consultant jnasby@xxxxxxxxxxxxx
Pervasive Software http://pervasive.com work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461
