With UDMA2 I get 26.x MEG/Sec device read timings with a 30 gig Maxtor
7200rpm drive. This is on an older Dell1300 server. I get 20.x MEG/Sec with
a 60gig Maxtor 5200 rpm.
This is with /sbin/hdparm -t after I have enabled 32bit IO and DMA.
Will the writes be the same as the read and what is the best way to find
out? I don't suppose just transering a file would be to accurate because of
disk disk buffers , sync, etc....
This is without RAID. If someone lets me know a good way to test out writes,
I'll be picking up a card next week. They are down to $119 for the 100mhz!!!
Thanks,
Steve
-----Original Message-----
From: Trent Piepho
To: video4linux-list@xxxxxxxxxx
Sent: 10/29/2000 12:26 AM
Subject: Re: [V4L] BTTV2
On Sun, 29 Oct 2000, Stephen Donnelly wrote:
> Alan Cox wrote:
> >
> > > modern IDE disks can only do about 16-20 MB/s *sustained writes*.
At the
> > > hub, I've seen a 43GB SCSI disk do 22MB/s, and tailing off after
that. A
> > > 10,000rpm 9GB scsi disk was performing similarly I seem to recall.
If
> >
> > Remember that as density goes up so does speed when not seeking..
9Gb disks
> > are much slower as they get less bits/rotation.
>
> Right, I was comparing 43 GB 5400rpm disks to a 9GB 10000rpm drive,
they
> preform about the same due to the higher linear density on the larger
> disks, as you said.
If you want a more modern comparison, these are bonnie bechmarks for a
dual
PII-400 (or PIII-550, it's been a while) with two 18GB 10k RPM IBM 18LZX
drives. At the time, they were IBM's fastest SCSI drives, but they have
faster ones now. The first is for 1 drive, the second is for two in a
RAID-0
config with the Linux md 0.90 driver. The test file was something like
1GB or
so.
-------Sequential Output-------- ---Sequential Input--
--Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block---
--Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU
/sec %CPU
1024 10364 96.8 27659 25.2 12699 24.2 10748 92.3 27221 13.8
369.3 2.5
-------Sequential Output-------- ---Sequential Input--
--Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block---
--Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU
/sec %CPU
1024 10691 99.6 60262 55.4 20568 42.3 11070 95.5 50852 31.5
416.7 3.4
Clearly, sustained output of 25MB/sec or more is possible. Of course,
if you
want some spare CPU and PCI/memory bandwidth, that's another thing.
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