Date: Sat, 27 Apr 2002 15:27:18 +0100 From: Brian Candler <B.Candler@pobox.com> To: "Andrew P. Lentvorski" <bsder@allcaps.org> Cc: freebsd-fs@freebsd.org, freebsd-net@freebsd.org Subject: Re: NFS clearing attribute cache in nfs_open Message-ID: <20020427152718.A16634@linnet.org> In-Reply-To: <20020426162442.N8693-100000@mail.allcaps.org> References: <20020426181535.B2748@linnet.org> <20020426162442.N8693-100000@mail.allcaps.org>
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On Fri, Apr 26, 2002 at 04:42:48PM -0700, Andrew P. Lentvorski wrote: > > ... Could it safely be made less restrictive, e.g. don't > > clear the cache when opening a file for read? > > In a word, no. Why couldn't the sysadmin be running "make installworld" > on the NFS server while you're running that program? By definition, for > better or worse, NFS is "stateless". The only way in which NFS can know > that your file hasn't changed (been deleted, renamed, etc) is to make that > round trip to the server. Sorry. Sounds fair. I was talking about the _attribute_ cache, but does re-fetching the attributes also tell the client that the _content_ of a file has changed? A version number, perhaps? > If you are really > into clusters with low-latency, you might want to look into something like > NFS V4 (Is anybody working on that on FreeBSD, anymore?), AFS, CODA, or > something more specialized. Those networked filesystems have a > bidrectional characteristic and cached state protocols so that they can > minimize communication. Will do. For a diskless bootup I think I am restricted to either NFS or ramdisk for the root filesystem though. Is it possible to replace the root filesystem with a different one after the system has started? Regards, Brian. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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