Re: scsi & ide disk speeds?
Svante Signell said:
> Hi,
> I've always thought SCSI disks are faster than the IDE disks, but this
> does not seem to be the case (at least for device reads). Anyone have a
> good explanation, or am I missing something?
as another pointed out, your scsi disk is pretty old, keep in
mind that transfer rate isn't everything, access time is also
as important if not more so then transfer rate. many SCSI disks
have access times rated at sub 7ms (some are at 5ms). Most IDE
disks are in the 10+ms range still. One of the fastest IDE drives
is the Western Digital 8MB cache series(Special Edition) they have
8.9ms access times..which is still higher then a 5400RPM IBM
2.01GB ultrawide scsi disk I had back in 1996 ..(7.5ms). I have
2 100GB Special ediiton drives in software raid1 connected to
a promise ata/100 controller, they are pretty fast. They don't
compare to my Ultra160 SCSI disk connected to a 29160N at work
though.
also hdparm probably isn't the best tool to benchmark SCSI disks since
it is geared towards IDE disks..
bonnie++ can probably give more real-world tests since it operates
on the filesystem level and copies/creates/deletes files of many
sizes in several different ways. It also uses a large amount of data,
the tests you posted seem to indicate 64MB worth of data is all that
was measured, bonnie++ usually uses (system ram)*2 worth of disk
space to test.
SCSI doesn't really start to shine though until you have multiple
devices on the bus.
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