Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!columbia!rutgers!caip!brl-adm!brl-smoke!smoke!baccala@USNA.arpa From: baccala@USNA.arpa (Brent W Baccala) Newsgroups: net.unix-wizards Subject: Re: BSD Unix machines hanging Message-ID: <4389@brl-smoke.ARPA> Date: Mon, 6-Oct-86 17:40:15 EDT Article-I.D.: brl-smok.4389 Posted: Mon Oct 6 17:40:15 1986 Date-Received: Tue, 7-Oct-86 23:55:12 EDT Sender: news@brl-smoke.ARPA Lines: 46 In <23407@gwen.cs.purdue.edu>, you write: >We have been experiencing a rather odd and intermittant problem with >our Unix machines. It is not confined to a particular machine or Unix; >it has happened with 4.2, 4.2 NFS, and 4.3 BSD on VAX 780, 785 and >uVAX II machines. > >Symptoms: The machines appear to lock up, users cannot get characters >echoed, console is hung. In short, the machine seems dead. The only >way to recover is a reboot. > >However, the machine is still running in a sense. One can ping the >machine in question, and it responds. One can open a TCP connection to >the machine, and the connection succeeds, but hangs at that point. We had the EXACT same problem with a PDP-11/55 running 2.9 BSD. It was much more consistant, though - ours would go down regularly every night (after hours, of course). I think fixed it this weekend (its been up for more than two nights straight - a major achivement). The problem appears to have been in a locally written version of "syslogd". I, too, suspected the network (though I'm far from a guru), but only looked briefly at the networking code. And since only one of our programs (a port of phone) uses syslog, I didn't think tracking down the bug justified the downtime that would be involved. Whether this problem is peculiar to our local syslogd, I don't know. Nor do I know exactly what triggers the bug; it make not be peculiar to syslogd either. It's interesting, but my experience has been that whenever there's a problem, turning off syslogd fixes it...maybe ours is just a broken daemon. Hope this helps (and let me know if you find the bug) -bwb - BRENT W. BACCALA - Aerospace Engineering Department U.S. Naval Academy Annapolis, MD "I do graphics work on an SGI Iris, fun work on a VAX 11/780, grunge work on an IBM XT"