Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!stanford.edu!msi.umn.edu!noc.MR.NET!gacvx2.gac.edu!dan From: dan@gacvx2.gac.edu Newsgroups: comp.dcom.lans Subject: Re: Wasteful use of file-servers Message-ID: <1991Jun17.192750.244@gacvx2.gac.edu> Date: 18 Jun 91 01:27:50 GMT References: <1991Jun11.175144.24736@cfctech.cfc.com> <1991Jun17.145457.7964@swift.cs.tcd.ie> Organization: Gustavus Adolphus College, St. Peter, Minnesota Lines: 41 In article <1991Jun17.145457.7964@swift.cs.tcd.ie>, omahony@swift.cs.tcd.ie writes: > In article , pcg@aber.ac.uk (Piercarlo Grandi) writes: >> Using a high speed machine with >> high speed disks is wasted as a file server; in practice file service is >> neither CPU bound nor IO bound, but network bound. > and >> Having a server than can provide an aggregate thruput of more >> than 1MB/sec. is entirely pointless, and any modern (16Mhz) 286 AT with >> some decent ESDI or SCSI disk controller and a couple of disks will do. >> > > The argument above makes perfect sense technically, but is in complete > conflict with current practice. Normally, small networks are built with > a number of medium or low-powered client machines, and a fast server machine. > > Does anyone have a counter-argument? > > Does the ESDI or other fast-bus make much of a difference e.g. 10%, 20%, 50%? A fast machine will generally have more I/O bandwidth. When considering PC compatables, I/O bandwidth is currently more important than CPU speed (medium performance 386 systems still have the same speed buss that the original PC AT had.) A fast server will reduce the amount of time between receiving a client request and sending the response. A fast network will reduce the time it take for the requests to be sent (in both directions.) A faster bus will decrease the time it takes to move data from the network interface, and from the disk controler. Almost all of the above parameters apply to clients as well. I suspect that the above could be reduced to some math, but the real point is that the network isn't the only bottleneck. Data must be pipelined from the client, through the network, arround inside the server, and back out to the client, each step represents a delay. A wide bus like MCA or EISA help since they can transfer more bytes per cycle. To take advantage of them, it is best to by a network card and disk controler that can take advantage of the full width of the bus. -- Dan Boehlke Internet: dan@gac.edu Campus Network Manager BITNET: dan@gacvax1.bitnet Gustavus Adolphus College St. Peter, MN 56082 USA Phone: (507)933-7596