Path: utzoo!utgpu!watserv1!watmath!att!att!pacbell.com!ucsd!swrinde!cs.utexas.edu!sun-barr!newstop!texsun!convex!convex.convex.com!thurlow From: thurlow@convex.com (Robert Thurlow) Newsgroups: comp.protocols.nfs Subject: Re: NFS writes and fsync(). Message-ID: Date: 23 Oct 90 21:35:52 GMT References: <1990Oct9.152612@objy.objy.com> <1990Oct14.082712.10811@objy.com> <1990Oct19.222754.17622@dg-rtp.dg.com> <3012@jaytee.East.Sun.COM> Sender: news@convex.com Lines: 36 In <3012@jaytee.East.Sun.COM> geoff@bodleian.East.Sun.COM (Geoff Arnold @ Sun BOS - R.H. coast near the top) writes: >Simple-minded question: if you want to introduce this best-effort >behaviour, why not do so on the client? Well, to a degree, we already have some control of this. I can set up to use synchronous writes through the buffer cache if I have a process that wants to see write(2) fail unless the server commits, or control timeouts on my attribute cache to force more consistency checks. But it's true that there's no per-filesystem control on the client. I'm not sure this is really important. >it's really a client issue: only the client knows whether or not data is >"precious" (to borrow an earlier attribute). I don't agree at all. The server is providing the storage, and the sysadmin of the server machine is the person best equipped to judge it's overall value; after all, he has to do the backups! I think individual client processes have a need to secure data, and that the server is the machine that really needs per-filesystem control over flushing policy. More client control in the form of a mount option would be welcome if it was easy to implement, though. >Bottom line: given the choice between changing the protocol and >its well-known semantics or changing an implementation of that >protocol, I'd rather change the implementation. I agree with the caveat that we need to tweak a few specific things ASAP without getting sidetracked by postscript-based protcols. #include Rob T -- Rob Thurlow, thurlow@convex.com or thurlow%convex.com@uxc.cso.uiuc.edu ---------------------------------------------------------------------- "This opinion was the only one available; I got here kind of late."