Date: Sat, 10 Feb 2001 11:37:25 -0600 From: Mike Meyer <mwm@mired.org> To: "Ted Mittelstaedt" <tedm@toybox.placo.com> Cc: questions@freebsd.org Subject: RE: Problems installing 4.x on large disks Message-ID: <14981.31829.637358.574815@guru.mired.org> In-Reply-To: <4704170@toto.iv>
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Ted Mittelstaedt <tedm@toybox.placo.com> types: > Anyway, pardon me for being bigoted, but IDE disks have no > place in a UNIX workstation. With supported PCI SCSI adapters > as cheap as they are, I for one fail to see why people are > willing to trade away gobs of performance for a few extra > gigs of hard disk space. Because they *aren't* trading "gobs of performance" for a few extra gig of hard disk space. While in the past, IDE drives pretty much sucked (they were slow and ate CPU), if you get modern UDMA drives, they'll keep up with all but the fastest SCSI drives in a drive-to-drive comparison. Of course, SCSI *is* a much better protocol. Two SCSI disks on one controller take up one IRQ, and will perform much better than two IDE disks on one controller, and slightly better than two IDE disks on two controllers - which takes up two IRQs. And it's more than just "a few extra gig". 50G scsi drives are around $500. 60G UDMA drives are under $200. You're paying 2x to 4x more per gigabyte for SCSI than IDE - and you only get extra performance in multi-drive systems. Bottom line: if you only have one drive, the extra cost of a SCSI drive would be better put into more RAM. For low-end servers, I buy the smallest IDE drive I can find (because that's *always* more disk space than I need). Sure, my workstation is SCSI - but it's got 5 or so devices on it. I'd be in IRQ hell if I tried to make it run with IDE devices. If you believe otherwise, I'd love to see the results of the disk throughput tests you've done to check it. I've still got mine somewhere, including both stock IDE (on the old wd device driver) and UDMA numbers on the IDE drive. This of course in *no way* detracts from what Ted said about large drives and BIOS problems. I'm just just not sure how SCSI helps solve that problems, because I've never tried to install a huge SCSI drive on a system. <mike -- Mike Meyer <mwm@mired.org> http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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