Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!think.com!snorkelwacker.mit.edu!bloom-beacon!eru!hagbard!sunic!sics.se!fuug!mcsun!unido!fauern!NewsServ!k2
From: k2@bl.physik.tu-muenchen.de (Klaus Steinberger)
Newsgroups: comp.protocols.nfs
Subject: Re: NFS performance
Message-ID: <k2.676879083@woodstock>
Date: 14 Jun 91 05:58:03 GMT
References: <1991Jun13.164017.29944@Firewall.Nielsen.Com> <625@appserv.Eng.Sun.COM> <1991Jun13.234448.16172@Firewall.Nielsen.Com>
Sender: news@Informatik.TU-Muenchen.DE
Organization: Technische Universitaet Muenchen, Germany
Lines: 37

kdenning@genesis.Naitc.Com (Karl Denninger) writes:

>>MIPS systems have an unsafe export option that allows you to turn off
>>this constraint - big performance win, big safety lose.

>There is no export option in the manual pages for RiscOS 4.51 which 
>addresses what you're talking about.  I just checked again; it's not there.

It's not in the exports file, it's in fstab, her is the relevant part of
the manpage (FSTAB(SysV)):

          nfs_sync|nfs_async
                    Typically, NFS performs synchronous writes;
                    however, performing asynchronous writes can
                    speed-up performance tremendously. This
                    option allows nfs servers to control their
                    local file system behavior for NFS write
                    requests. Synchronous writes guarantee the
                    data has been written to disk rather than
                    guaranteeing that a server has correctly
                    received a write request. This only becomes
                    an issue if a server crashes during a write.
                    See kopt (8) to change the global default
                    value. nfs_async is the current default.

As you can see, the default for the server is ASYNC. You can change the
behaviour on a per filesystem basis at mount time, or a system startup
globally with kopt. We use the default of async, and we are happy.

Sincerely,
Klaus Steinberger

--
Klaus Steinberger               Beschleunigerlabor der TU und LMU Muenchen
Phone: (+49 89)3209 4287        Hochschulgelaende
FAX:   (+49 89)3209 4280        D-8046 Garching, Germany
BITNET: K2@DGABLG5P             Internet: k2@bl.physik.tu-muenchen.de