Gordon Johnson wrote:
> I'm looking at my hard drives performance. It's a western digital 5400 rpm
> with a cache of 512. It's configured to run UDMA66.
>
> hdparm -Tt gives me...
>
> Timing buffer-cache reads: 128 MB in 1.36 seconds = 94.12 MB/sec
> Timing buffered disk reads: 64 MB in 4.98 seconds = 12.85 MB/sec
>
> I'm intending to go to a 7200rpm UDMA100 drive with a 2mb cache.
> Anyone know what sort of performance boost to expect?
It depends. (-:
The 12.85 Mb/sec figure is very low. I just checked the four nearest
drives I can get to, and the slowest is 19.16 MB/sec. Your buffer
cache bandwidth isn't so great either. On a 450MHz Pentium II w/
440BX chipset (we loved that chipset), I saw 115 MB/sec. Unless your
CPU is slower than 450 MHz, there's something wrong. (If your CPU is
slower, replacing it will almost certainly make a bigger difference
than replacing the disk.)
So maybe the system wasn't really idle when you ran the test, or your
drive is set up wrong, or...? Are your CD-ROM and Zip drives on the
other IDE connector?
Does hdparm show your parameters similar to this?
root@jogger-egg~# hdparm /dev/hda
/dev/hda:
multcount = 16 (on)
I/O support = 1 (32-bit)
unmaskirq = 0 (off)
using_dma = 1 (on)
keepsettings = 0 (off)
nowerr = 0 (off)
readonly = 0 (off)
readahead = 8 (on)
geometry = 15017/255/63, sectors = 241254720, start = 0
busstate = 1 (on)
The important ones are multcount, I/O support, using_dma, and
readahead. Some drives want a different multcount than 16. Here is
what /usr/share/doc/hdparm/README.Debian says (on Debian, of
course...)
> hdparm for Debian
> -----------------
>
> To get the best performance out of your hard drive turn on DMA support in the
> kernel and enable 32bit IO (-c) and multiple sector I/O (-m) with hdparm. You
> can find out the number to use for -m by using -i and reading MaxMultSect.
>
> -- Christopher L Cheney <[EMAIL PROTECTED]>, Wed, 21 Nov 2001 15:51:14 -0600
Here are the performance numbers I collected in a hurry.
On host jogger-egg, 450 MHz Pentium II, Intel 440BX chipset:
root@jogger-egg:~# hdparm -i /dev/hda | grep Model=
Model=IC35L120AVVA07-0, FwRev=VA6OA52A, SerialNo=VNC602A6C394MA
root@jogger-egg:~# hdparm -Tt /dev/hda
/dev/hda:
Timing buffer-cache reads: 128 MB in 1.12 seconds =114.29 MB/sec
Timing buffered disk reads: 64 MB in 2.89 seconds = 22.15 MB/sec
root@jogger-egg:~# hdparm -i /dev/hdb | grep Model=
Model=IBM-DTLA-307045, FwRev=TX6OA50C, SerialNo=YM0YM014000
root@jogger-egg:~# hdparm -Tt /dev/hda
/dev/hda:
Timing buffer-cache reads: 128 MB in 1.11 seconds =115.32 MB/sec
Timing buffered disk reads: 64 MB in 2.84 seconds = 22.54 MB/sec
On host tivopc, *SINGLE* 1400 MHz Athlon, AMD 760MP chipset, cheap disks:
[root@tivopc bmiller]# hdparm -i /dev/hda | grep Model=
Model=QUANTUM FIREBALLlct15 30, FwRev=A01.0F00, SerialNo=314011918369
[root@tivopc bmiller]# hdparm -Tt /dev/hda
/dev/hda:
Timing buffer-cache reads: 128 MB in 0.57 seconds =224.56 MB/sec
Timing buffered disk reads: 64 MB in 3.34 seconds = 19.16 MB/sec
[root@tivopc bmiller]# hdparm -i /dev/hdb | grep Model=
Model=IBM-DTLA-305040, FwRev=TW4OA60A, SerialNo=YJ0YJT09332
[root@tivopc bmiller]# hdparm -Tt /dev/hdb
/dev/hdb:
Timing buffer-cache reads: 128 MB in 0.56 seconds =228.57 MB/sec
Timing buffered disk reads: 64 MB in 2.44 seconds = 26.23 MB/sec
--
Bob Miller K<bob>
kbobsoft software consulting
http://kbobsoft.com [EMAIL PROTECTED]
