Date: Wed, 10 Apr 1996 22:09:37 +0200 (MET DST) From: J Wunsch <j@uriah.heep.sax.de> To: jin@george.lbl.gov (Jin Guojun[ITG]) Cc: joerg_wunsch@uriah.heep.sax.de, freebsd-bugs@FreeBSD.ORG, gibbs@freefall.freebsd.org, jin@george.lbl.gov, jkh@time.cdrom.com Subject: Re: Unsuccessfully to install 2.2-960323 SNAP Message-ID: <199604102009.WAA01250@uriah.heep.sax.de> In-Reply-To: <199604100019.RAA26161@george.lbl.gov> from "Jin Guojun[ITG]" at Apr 9, 96 05:19:57 pm
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As Jin Guojun[ITG] wrote: > A little more information. The FTP installation also pauses at this point > for a second, and then continues. There must be some negotiation going on > at this point and it is broken for NFS: > > ... > stand/ee > stand/df > stand/cat > stand/ls > hanging Well, it's the first ``real file'' that is being fetched from the server at this moment: j@uriah 94% gzcat < root.flp | cpio -ivt drwxr-xr-x 3 root wheel 0 Feb 14 11:09 . drwxr-xr-x 3 root wheel 0 Feb 14 11:09 stand drwxr-xr-x 11 root wheel 0 Feb 14 11:09 stand/info drwxr-xr-x 2 root wheel 0 Feb 14 10:02 stand/info/bin -rw-r--r-- 1 root wheel 1799 Feb 14 10:02 stand/info/bin/bin.inf ... -r-xr-xr-x 59 root bin 0 Feb 14 09:34 stand/ee -r-xr-xr-x 59 root bin 0 Feb 14 09:34 stand/df -r-xr-xr-x 59 root bin 0 Feb 14 09:34 stand/cat -r-xr-xr-x 59 root bin 0 Feb 14 09:34 stand/ls -r-xr-xr-x 59 root bin 811008 Feb 14 09:34 stand/root_crunch (End of archive.) All the ``files'' above are actually hard links to root_crunch. So it really looks like the generic NFS hang problem. For some reason, your NFS server is pumping packets quicker than your ethernet card can pick them up from the wire. However, the default NFS block size is 8 KB, and NFS can only ``think'' in full NFS blocks, so it retransmits the 8 KB block again. Apparently, this will hang the system. The ``slow NFS'' was supposed to get around it by reducing the block size to 1 KB, so it always fits into a single UDP packet. It should always be possible to retransmit it. If your ethernet card is very lossy for some reason, the UDP/timeout/retransmit negotiation of NFS will however drastically slow down the overall data rate, quite more that TCP will. I've also noticed that my installation attempts required ``slow NFS'' where i can't seem to remember that i had to specify this before. (Server and client are both sluggish 3C503 8-bit cards.) -- cheers, J"org joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE Never trust an operating system you don't have sources for. ;-)
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