IDE vs SCSI drives

[Kevin Buettner]

On Oct 18,  9:28am, Craig White wrote:

> Perhaps someone will clue me in to what IIRC actually means.

IIRC == "If I Recall Correctly".

> My first thought was that you are comparing new IDE drive technology to 4
> year old SCSI technology. 

The SCSI technology is a little over a year old.  As I mentioned in
my reply to David, the SCSI drive runs at 7500 RPM and the IDE drives
only run at 5400 RPM.

> SOA of SCSI is ultra3 (160mbs) and ultra
> controller like the Adaptec 29160 and 10,000 - 15,000 WD ultra3 drive would
> probably dust the IDE's but you surely caught my attention with your post.

The SCSI controller is an Ultra2 which should be capable of 80MB/sec.
I didn't see anywhere close to that kind of performance though.  (12.67
MB/sec for reads; 8.43 MB/sec for writes (copying from the kernel's
buffer cache.)

> Then there are hardware RAID controllers that should really optimize
> performance.

I know.  When I purchased the IDE drives recently, I was shooting for
cheap and reliable (which is why I got two and am mirroring them) rather
than high performance.  This is why I was amazed when these drives
performed better than my SCSI drive.

Also, it seems to me that with regard to performance you might be better
off just putting a boatload of memory in the box... eventually most of
the stuff that you read off of disk will be in the kernel's buffer cache.

> Also I don't seem to get the same reliability from IDE on servers that I get
> from SCSI - however most of my firsthand comes from Windows NT which seems
> to pretty well thrash an IDE drive in a years time.

I had the same concerns.  I have very little direct experience with IDE,
but I've read dire warnings regarding IDE in a number of places.  Again,
that's why I decided to get two IDE drives and mirror them.