Date: Sun, 04 Jan 1998 22:56:25 -0400 From: =?iso-8859-1?Q?=22Luis_E=2E_Mu=F1oz=22?= <lem@cantv.net> To: spork <spork@super-g.com> Cc: jbutt@mwci.net, freebsd-isp@FreeBSD.ORG Subject: Re: [fbsd-isp] Designing for a very large ISP Message-ID: <3.0.5.32.19980104225625.007bb280@pop.cantv.net> In-Reply-To: <Pine.BSF.3.96.980104164317.17626C-100000@super-g.inch.com> References: <199801042025.OAA22797@subcellar.mwci.net>
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At 04:50 PM 04/01/1998 -0500, spork wrote: [snip] >At this point we see different behaviour. The client sometimes panics >(haven't been at the console to see why), or the command hangs and is >un-killable. The only way to get rid of the phantom mount seems to be a >reboot of the client.... A panic is definitely not correct, however a command waiting forever is normal. These are the semantics of a 'hard' mount on NFS. If you want the processes to timeout, you need a 'soft' mount. This should only be done if you really know for sure that you want that. Picture a mail server trying to deliver mail to a failed NFS mailbox. The actual timeout might be in the close() call. If this fails, probably will go undetected and the mail will be lost in the bit bucket. This is why the default mount stile is 'hard'. You also cannot unmount a FS while there are operations queued for the NFS server. You need the server to be back up before you can unmount. If this doesn't happen, then we have another abnormal situation... As a rule of thumb, I assume that the clients will be down of the NFS server dies for some reason. Sometimes you may think that the client may continue with other tasks unrelated to the unresponsive filesystems, but eventually there are going to be enough blocked processes so as to stop the client. We've only sporadically used NFS mounts to export CDs and other stuff in our lab from FreeBSD 2.2.5 servers, with excellent behavior. >Seems to work well except for this behaviour, but I wouldn't want to put >it in production. Nor do I. I tend to dislike NFS on an ISP core :) [snip] -lem
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