Re: scsi tuning
On 21 Apr, this message from John Schmidt echoed through cyberspace:
> On Sunday 21 April 2002 08:36 am, John Schmidt wrote:
>> Hi,
>>
>> I have a Power Tower Pro with a G3/466 card running with scsi drives. I am
>> running woody with kernel 2.2.20. The drive is hooked up to the internal
>> scsci bus which supposedly can do 10MB/sec transfers (I think I got the
>> right specs; I do know that the external bus is half the speed of the
>> internal). The drive in question is:
>>
>> mesh: target 1 synchronous at 10.0 MB/s
>> Vendor: QUANTUM Model: FIREBALL_TM3200S Rev: 300X
>> Type: Direct-Access ANSI SCSI revision: 02
This disk is very low-speed (and low-quality on top of that). There's no
reason to put that on a faster bus.
> Oops, I goofed and copied the wrong drive:
>
> Vendor: QUANTUM Model: FIREBALL SE8.4S Rev: PJ0A
> Type: Direct-Access ANSI SCSI revision: 02
> Detected scsi disk sdc at scsi0, channel 0, id 2, lun 0
> mesh: target 3 synchronous at 10.0 MB/s
I don't know that disk, but I did get those hdparm numbers you reported
for all (reasinably fast) SCSI disks on the internel (aka MESH) SCSI on
oldworlds. If that Fireball SE is a lot faster than the TM (which I
doubt..), than you could add a more recent SCSI card (some SYM or
Adaptec...), but that won't be a cheap solution.
I have myself made very good experience with a Promise IDE card
(Ultra66) with a fast IDE disk, and I get thes hdparm numbers:
/dev/hda:
Timing buffer-cache reads: 128 MB in 2.90 seconds = 44.14 MB/sec
Timing buffered disk reads: 64 MB in 5.19 seconds = 12.33 MB/sec
Keep in mind that this is with a 3-year old disk; today's disks are a
lot faster.
However, as you can see when comparing buffer reads and disk reads, the
oldworld systems are very limited performance-wise, compared to today's
standards. So, my adice would be that if you do want to invest in it,
get a cheap IDE card and a good value 7200 RPM IDE disk. Today's IDE's
beat 2-years old SCSI disks....
Keep in mind however that the majority of IDE cards are not bootable on
the Mac, so you would need to keep a SCSI disk for booting.
Cheers
Michel
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