Date: Wed, 23 Jul 1997 14:20:23 -0400 From: Dave Alderman <dave@persprog.com> To: Michael Smith <msmith@atrad.adelaide.edu.au> Cc: Anthony.Kimball@East.Sun.COM, kuku@gilberto.physik.rwth-aachen.de, sos@sos.freebsd.dk, freebsd-hardware@FreeBSD.ORG Subject: Re: building RAID systems Message-ID: <33D64B67.EF15E653@persprog.com> References: <199707231558.BAA09859@genesis.atrad.adelaide.edu.au>
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Michael Smith wrote: > Actually, you should go back and look at what SCSI drive prices are > doing at the moment. I can get a 5400 RPM 4GB ultra scsi IBM disk for > less than 30% more than the corresponding IDE model. IBM's pricing is > pretty keen at the moment. Yeah! What he said! Additionally, IDE's and SCSI's are usually not equivalent in base performance and capacity specs. The highest RPM IDE I know of is 5400 RPM (with typical being 4500-4800) while the fastest SCSI is 10000 RPM (with typical being 5400-7200). The biggest IDE is now 7GB - SCSI is at least 9GB (and possibly more). SCSI's usually have bigger caches as well. IDE's are good for workstation apps but for data intensive server work (or data intensive workstation work) SCSI is a better way to go. That being said, I heard of somebody making an IDE RAID box - this may be OK since the relatively poor performance of the individual disks may be masked in the performance advantage of a hardware RAID virtual disk. All of the usual advantages of SCSI could be implemented in the RAID controller itself. Of course the price of the controller may offset the savings on the drives. One more thing - has anyone noticed when one of the trade rags tests CPU usage on CRROM drives a funny thing happens - IDE CDROMs take 80% or more CPU while SCSIs take less than 20% when reading? While we're completely off the subject - how did these manufacturers coerce a CD-R drive into working on an IDE bus? I noticed that every one of these drives for sale in one catalog had a "special" IDE controller. What is this all about? Thank you for tolerating my unsolicited rant :-) -- It's not my fault! It's some guy named "General Protection"! --Ratbert David W. Alderman dave@persprog.com
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