Date: Tue, 19 Aug 97 02:33:28 -0400 From: curt@kcwc.com (Curt Welch) To: Tom Samplonius <tom@sdf.com> Cc: scsi@FreeBSD.ORG, curt@kcwc.com Subject: Re: expected performance with DPT RAID-5... Message-ID: <9708190633.AA20893@mail.kcwc.com>
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Tom wrote:
> "cd" to one of the RAID-5 file systems and do a "dd
> if=/dev/zero of=testfile bs=64k count=1000". That will
> create a file called "testfile" 64MB in length (64k x
> 1000), and tell you how long it took to write it.
> Then reboot (the only way I know of clearing the FreeBSD
> file cache, and the DPT cache), and do a "dd if=testfile
> bs=64k of=/dev/null" to read the file back.
> On the write test I get about 3500000 bps, and the
> write test about 9200000 bps. These results don't seem
> very good too me.
On bus 0 I have fast/wide drives but I currently have
the speed limited to 5Mhz (slow/wide?).
On bus 1 I have ultra/wide drives and the bus is currently
limted to 5Mhz (trying to work out SCSI problems), but I
put it back to 20 Mhz for some of these tests.
Numbers are all bytes per second (output from dd).
On write, I see 1,800,000 on bus 0 at 5 Mhz
2,500,000 on bus 1 at 20 Mhz.
2,400,000 on bus 1 at 5 Mhz
On read, I see 6,300,000 on bus 0 at 5 Mhz.
5,400,000 on bus 1 at 5 Mhz.
This is with 2.2.2-RELEASE and the DPT 1.1.10 driver with
the following options set:
options DPT_USE_SINTR=1
options DPT_MEASURE_PERFORMANCE
options DPT_TRACK_CCB_STATES
options DPT_HANDLE_TIMEOUTS
options DPT_COMMAND_SPLHIGH
options DPT_INTR_CHECK_SOFTC
The ultra-wide drives are Quantum Vikings. I also have one
of these drives connected to an Adaptec 9240UW card in the
same system. Your test on that drive produces:
On write, I see 8,400,000 on AHA at 20 Mhz
read is about the same - but I don't want to reboot again to
do a "clean" no cache test. I suspect it would produce about
the same number however.
This test: dd if=/dev/rsd1c bs=8k of=/dev/null count=10000
produces a rate of 9.3 MB/S on the AHA.
On the DPT (bus 1 at 5Mhz), it produces a rate of 4.0 MB/S.
I'm not over impressed with these numbers for the DPT, but
then I'm still dealing with unknown SCSI problems with this
set-up.
Curt
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