Xref: utzoo comp.sys.apple:13771 comp.sys.apollo:2841 comp.unix.aux:1011 comp.unix.questions:14193 comp.sys.mac:33241 comp.sys.dec:1371 Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!purdue!bu-cs!bzs From: bzs@bu-cs.BU.EDU (Barry Shein) Newsgroups: comp.sys.apple,comp.sys.apollo,comp.unix.aux,comp.unix.questions,comp.sys.mac,comp.sys.dec Subject: Re: Academic workstations -- Followups to comp.unix.questions ONLY Message-ID: <32705@bu-cs.BU.EDU> Date: 10 Jun 89 15:10:16 GMT References: <507@lclark.UUCP> Distribution: usa Organization: Boston U. Comp. Sci. Lines: 54 >This should give you better performance because local >disks should be faster than networks, but it also adds to the cost and >administration effort. > > Rick Daley > rpd@Apple.COM Bad guess, go measure it, because servers almost always have faster disks, controllers and bigger disk buffers remote disks are usually faster than local disks (assuming a reasonable network loading which doesn't have to be zero.) An ethernet can deliver data at almost 1MB per second, go look at the specs on your standard 27msec SCSI cheapo, 20KB/sec is not unusual for maximum disk transfer rate, about 1/40th the speed of an ethernet. In some cases remote disks are much faster, particularly where the server CPU is much faster (and the disk system) and your process is causing some amount of parallelism to occur (this doesn't have to be purposeful, something simple like a find with a grep on each file can end up exploiting both CPUs as one resolves the file system as the other pumps away at the raw data.) Remember all those gripes about the overhead of namei()? Where do you think namei() is running in an NFS environment? Many network load problems are due to badly configured or managed networks with lots of junk traffic (eg. ARP or other broadcast screamers going unchecked.) However, I will agree that blaming it on the diskless workstations is a wonderful alibi, the yokels believe you and rarely ask you to actually do your job and find out what's really causing the problem. It's the diskless workstations, it's the diskless workstations (we know those diskless workstation users will never buy the local disks you recommend so it's a safe bet to blame it on them.) Another problem is political, the enforced memory shortage has temporarily made the disk/memory balance unnatural. But don't confuse economic realities with technical ones. I agree none of this would apply to a Mac-II acting as an NFS server, it doesn't support the disk architecture necessary to get any performance advantage over a local disk. I am not saying there aren't cases where a diskful workstation is far better, I'm just saying most people don't know what they're talking about or have motives other than understanding the technology. -- -Barry Shein Software Tool & Die, Purveyors to the Trade 1330 Beacon Street, Brookline, MA 02146, (617) 739-0202