Path: utzoo!news-server.csri.toronto.edu!cs.utexas.edu!usc!nic.csu.net!beach.csulb.edu!csus.edu!wuarchive!zaphod.mps.ohio-state.edu!caen!hellgate.utah.edu!fcom.cc.utah.edu!npd.novell.com!newsun!keith From: keith@ka.excelan.com (Keith Brown) Newsgroups: comp.sys.novell Subject: Re: NFS Support in NetWare Message-ID: <1991Mar2.013301.8599@novell.com> Date: 6 Mar 91 02:18:43 GMT Sender: news@novell.com ( Lines: 48 The News Manager) Nntp-Posting-Host: ka Reply-To: keith@ka.excelan.com (Keith Brown) Organization: Novell, Inc. San Jose, California References: <1991Feb21.234900.11916@novell.com> <6614@spdcc.SPDCC.COM> <1991Mar01.050450.17708@xstor.com> <1991Mar1.145839.13285@cimage.com> Date: Sat, 2 Mar 1991 01:33:01 GMT In article <1991Mar1.145839.13285@cimage.com> brian@dgsi.UUCP (Brian Kelley) writes: > >And what happens to your hard mounted NFS clients when your server goes down, >losing 3-4 megabytes of cached data? > This needn't be an issue if you don't want it to be. One of the configuration parameters of NetWare NFS is "CACHE_WRITE_THROUGH". Setting this parameter to "on" puts us into "UNIX mode" and we dutifully make sure write operations to the server hit the magnetic dots before we respond to the request. As you would expect, this will cost you some performance but we still find that we're head and shoulders above UNICES on a comparable hardware platform. However, you will note that it is possible to make the NetWare v3.11 underlying file system rather robust, rather cheaply. Buy yourself a second hard disk, plug it into your controller and fire up our disk mirroring capabilities and you just guarded your 3-4 megabytes of cached data against a disk failure. Splash out on an additional HD controller, fire up our disk duplexing features and you just protected your 3-4 megabytes of cached data against a disk or controller failure. Buy yourself an uninterruptible power supply and load up UPS.NLM and you just guarded your 3-4 megabytes of cached data against your local klutz kicking the plug out of the wall. Etc..... NetWare v3.11 does try to flush it's caches within 3 seconds if it can anyway, so thats still a little better than your average UNIX system. I'm uncertain as to which UNICES actually have the ability to disable cache write through at all? Perhaps it can be done on some by adb(1)ing the kernel. Anyone care to enlighten me? It still wouldn't buy UNIX based NFS servers very much though. Why? Well, someone once told me that UNIX systems have these things called user processes to be concerned about. If this is indeed the case, that must mean they are unable to blow open every last byte of their remaining memory to an enormous disk cache. Hmm... I imagine that this must severely impact their ability as NFS servers? Could this be true?? I wonder! Keith - Keith Brown Phone: (408) 473 8308 Novell San Jose Development Centre Fax: (408) 433 0775 2180 Fortune Dr, San Jose, California 95131 Net: keith@novell.COM