Date: Thu, 22 Jun 2000 09:43:22 -0500 (CDT) From: Mike Meyer <mwm@mired.org> To: questions@FreeBSD.ORG Subject: SCSI drives and things (was: questions-digest V4 #1709) Message-ID: <14674.9738.525554.380384@guru.mired.org> In-Reply-To: <bulk.13632.20000622070822@hub.freebsd.org> References: <bulk.13632.20000622070822@hub.freebsd.org>
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Various people wrote: > From: Nicholas Lysaght <nlysaght@one.net.au> > > Hewlett Packard DeskJet 694C Printer, and ScanJet 5p Scanner. > ... > Finally the scanner. Sane is now on my ports, but I it runs on a > proprietry scsi card supplied by HP. Do you think there's any > chance of me getting it to work in BSD under Sane or something > similar? If it's really a SCSI scanner, you should be able to use any SCSI controller that is supported by FreeBSD, not just the one from HP. I'm using an Artec SCSI scanner attached to an Adaptec aic7890. If you don't already have a SCSI controller, it might be worth a bit of time seeing if yours is already supported (install it, check dmesg for id information, and posting that here would be a good start). > ------------------------------ > From: <chris.smith@raytheon.co.uk> > Subject: SCSI vs ATA disks > My box is thrashing badly with 30 users over telnet doing various things (cur > specs:- 233/128M/20G ATA33 disk)! vmstat shows that memory really isn't a > problem (it hardly touches swap) but it's in iowait 70% of the time (excuse the > solaris term). It's being upped to a P2/400 with 256M RAM and a nice Asus > board next week but is still stuck disk wise (I assume that is whats really > causing the problems). > Is it worth putting a 2-4 SCSI-UW disks in instead? Depends. Did you check iostat to see what it said about your drives? Also, what's the cpu utilization (system vs. user vs. idle)? Also, do you have your IDE drives cranked up properly? The GENERIC kernel doesn't. Make sure you've got DMA and other such things turned on on the drive. I've gotten better than a factor of three improvement in throughput on ATA drives by doing that. Once you've got all that done, if you have the resources in your machine and a spare ATA33 drive, you might try installing that on the second IDE controller and doing a bit of balancing (iostat is your friend). If that improves things, then you're definitely on the right track. Going to SCSI drives from there will help even more, and the load balancing you did for testing will come in handy as well. > If so, what is likely to > be the best cost/performance economy:- > 4 x 4.5Gb disk > 2 x 9.1Gb disk Generally, more drives is better. But the 9.1Gb drives are liable to be both faster and noticably cheaper/mb (that was true a year and a half ago). > Also, are those I-Will controllers any good? I don't really want to fish out > for something like an Adaptec controller when an I-Will one will do the job > probably just as well... Sorry, I can't help you. If they are cheap enough, one thing to consider is putting in more than one of them. That will buy some extra performance. > ------------------------------ > From: "vagner" <george@vagner.com> > Subject: offtopic fast hard drive > > I am looking for a suggestion for a hard drive > that will push my new aha-2940u2w to the limit. One hard drive won't do it. Two may not be enough. > i been looking at seagate barracuda's and IBM's > but they are so far in price difference i dont know > whay one is / is not superior to the other? Last time I checked, those were good ones to use. At that time, the IBMs had higher RPM rates than, which translates to more bits under the head (and hence over the wire) per second. > can anyone really say which one is the fastest for my card? Sure. Send me one of each, and I'll run some tests and get back to you :-). > WD has some impressive pricing right now for a 18 gig > but why is it only half as much as a seagate? What are the specs on the two drives? On-drive cache, rotation speed, track-to-track step time, etc? That will have a lot to do with it. > thanks sorry to bother you with a trivial question. Oh, it's not a trivial question. It's a very deep question. <mike To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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