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Re: [K12OSN] SCSI Reliability



I think that your Tech friend has an opinion, probably not based on a large sample
population...  I used LVD SCA scsi in servers, and IDE in work station type PCs. I se no
difference in the reliability, so long as adequate cooling is present.

If you look, the rotating drive mechanism is often the same on modern SCSI and IDE
drives. The circuit board mounted on the drive is what varies. Consequently, the
reliability of the rotating drive component is likely very similar.

Note that the circuit board on the IDE Master drive is critical, if it fails, you will
probably lose access to the slave as well.  On SCSI, the failed drive is less likely to
obstruct access to the other drives on that scsi cable, because the brains are on the
SCSI adapter. And that is much less likely to get overheated because the spacing allowes
better air flow.

I have run SCSI LVD SCA in RAID 5 setups for more than 4 years. All drives are 3.5 inch
low profile (1 inch height) drives. They are packed tight in the raid cage, no extra
space in between drives. Coolong is important, the raid cages I use all have attached
cooling fans, and I check that the fans are still spinning once in a while.

Out of 9 drives running 24/7, only one has failed. The new drive rebuilt its data with no
loss of data.

SCSI is expensive, IDE is less expensive.  If you want cheap reliability, get one of the
IDE RAID conrollers that run 3, 4 or even more drive channels (one drive per ide cable).
The adapter is priced high like raid SCSI adapters, but the drives are a lot cheaper to
buy, especially the drives over 18GB. Big ATA100 drives are dirt cheap compared to SCSI.

That's my opinion, at least.






--- Daniel Loomis <dloomis cox-internet com> wrote:
> I was talking the other day with the service manager of a computer systems and 
> service provider in our area about implementing SCSI drives on our k12ltsp 
> server.  He was not terribly encouraging.  His experience with lots and lots 
> of servers (most running NT or Win2k) has been with repeated failures of SCSI 
> drives . . . much more so than with IDE HDs.  He is especially down on 
> Seagate SCSI drives as he has had to replace a number of those lately.
> 
> I was under the impression that SCSI drives are at least as reliable as those 
> using IDE interfaces.  My last SCSI drives were those installed on an Autocad 
> Server running Novell about 10 years ago.  I guess the move to 10,000 & 
> 15,000 rpm drives could be a major factor in their reliability, but have not 
> read anything to that effect online.  I did not ask if the failed drives had 
> been equipped with hd cooling fans.
> 
> Has anyone had similar experiences or is the anecdotal experience of my 
> acquaintance unusual?
> 
> Dan
> 
> P.S.  My friend did say that SCSI tape drives were DEFINITELY the way to go.
> -------------------------------------
> Dr. Daniel Loomis
> El Dorado, Arkansas
> 
> 
> 
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