Date: Sun, 11 Feb 2001 01:14:31 -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: <14982.15319.193759.406761@guru.mired.org> In-Reply-To: <002d01c093cb$9ba1f2e0$1401a8c0@tedm.placo.com> References: <14981.53225.50061.220090@guru.mired.org> <002d01c093cb$9ba1f2e0$1401a8c0@tedm.placo.com>
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Ted Mittelstaedt <tedm@toybox.placo.com> types: > > Yup. And the last price/performance study I saw for that came down in > > favor of a custom RAID box that had a bunch of UDMA drives in it and a > > SCSI port to talk to the system. UDMA controllers are cheap enough you > > can throw one in with the HDA and still beat SCSI prices. > Yes, I've seen more of those kinds of things, as well as the IDE raid cards. > While they aren't yet as standard as a SCSI setup who knows we may see > them in wide use one day. I was actually shocked to discover this. But I could buy the custom IDE box for less than it would have cost to buy the SCSI drives and do this in software. > Certainly it's to the drive manufacturers advantage to kill off one > specification > over another so that eventually all disk drives are of a single type. Maxtor already quite making SCSI drives. I was dissapointed, as I remember getting good results with their SCSI drives (actually, vendor-rebranded versions) in the past. > Now, if you can only spend, say $500 on a new system that has IDE and for > an extra $300 you can make it SCSI, well then you probably are going to be > making those IDE/SCSI/RAM tradeoffs. But if your going to be spending $1500 > on a system, in my opinion you have gotten to the point that an extra $300 > to get that measure of reliability and performance of SCSI is nothing. > Keep going up the price scale, to say $5K, and the cost difference becomes > negligible. I wouldn't argue with those numbers - but these days, $1500 is more than the average workstations costs. > But, if I was only given $500 to put together a low-cost server, I wouldn't > go out and buy brand new hardware with IDE and a cheap motherboard and box. > I'd buy an older server-class box from Ebay or some used equipment dealer. > Many of them come with raid arrrays, multiple CPU slots, and a lot of other > assorted goodies and their reliability is going to be immensely better than > a clone box slapped together with components designed for the home user. > I'll always trade off performance for reliability in a tight-cost situation, > and let me point out that even an older Pentium Pro 200 with a RAID array > of slower disk drives is perfectly able to totally saturate > Ethernet if your just using it as a fileserver. There's a point in server > work where more performance on the server doesen't buy you anything, > depending, of course, on what your doing on the server. If I were going to build a fileserver, I'd do it that way as well. And the point that "more performance doesn't buy you anything" is an argument *against* SCSI, not more it. You spend more on SCSI to get better performance. > > Again, if you don't believe my numbers, run your own tests and tell us > > about it. > There's that saying about lies, damn lies, and benchmarks. If your seeing > better > performance from a 10MB IDE disk than a 10MB SCSI disk, for that statement > to > have any validity you really need to post your setup with model numbers, > adapter cards and all that. Do I believe that you saw that difference? > Yes, > because it's certainly possible to put a SCSI disk with a slower seek time > against an IDE disk and get better numbers from the IDE. It also depends > a lot on the test too, what kind of data was being written back and forth > and > all that. Just the opposite in this case. The SCSI drive was a Seagate Barracude 9LP on a 7890, 7200 PRM with a 7.4ms seek time. The IDE drive was a Maxtor DiamondMax plus, 7200rpm with a 9ms seek time. The test software was bonnie. > I'm a SCSI bigot because in all the servers I've worked on, > I can count the number of failures on SCSI disks that wern't full-height on > the fingers of one hand. I've lost count of the IDE disks I've sent back > for > replacement. In all the workstations I've worked on, the SCSI ones > were always faster than IDE. And I've never had as many incompatability > problems with SCSI systems as with IDE. Now, maybe I need to come into the > 21st > century, but I'll always choose SCSI over IDE if I have a choice. I haven't *ever* had an IDE drive fail. Then again, I didn't buy PC hardware until slightly more than two years ago (because doing performance tests against RISC hardware showed that the price/performance for PC hardware blew the RISC hardware away), and didn't start using IDE drives until about 18 months ago, after I did the tests above. The only IDE drives I've seen die were old ones (~600 meg sizes) that came showed up with second-hand hardware. On the other hand, I've lost track of the number of SCSI disk drives I've seen fail, in both full and half-height sizes. I admit that if I were going to build a system for that needed 7x24 reliability and was mission critical, I wouldn't be buying IDE drives. I wouldn't buying PC hardware, either. My experience is that it's not as reliable, and you can't properly manage it over a serial line (well, not without unusual hardware). <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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