Date: Tue, 2 Jan 2007 10:04:38 -0800 From: Jeremy Chadwick <koitsu@FreeBSD.org> To: Gavin Atkinson <gavin.atkinson@ury.york.ac.uk> Cc: freebsd-stable@freebsd.org Subject: Re: Interrupt (SCSI?) hang on 4.x Message-ID: <20070102180438.GA81454@icarus.home.lan> In-Reply-To: <1167755991.84652.6.camel@buffy.york.ac.uk> References: <20070102153608.GA78405@icarus.home.lan> <1167755991.84652.6.camel@buffy.york.ac.uk>
next in thread | previous in thread | raw e-mail | index | archive | help
On Tue, Jan 02, 2007 at 04:39:51PM +0000, Gavin Atkinson wrote: > On Tue, 2007-01-02 at 07:36 -0800, Jeremy Chadwick wrote: > > # vmstat -i > > ata0 irq14 6 0 > > fxp0 irq10 14874 28 > > mux irq11 65028 125 > > fdc0 irq6 1 0 > > sio0 irq4 948 1 > > clk irq0 516187 998 > > rtc irq8 66071 127 > > Total 663115 1282 > > Do any of these numbers continue to increase after the hang? You may > find that if you are already logged in over the serial port before the > hang and have run vmstat recently, it'll still be runnable due to it > being cached. When this problem is happening, at the login: prompt (via serial console) once one types "root" and hits enter, one never gets a Password: prompt. This is likely because getpwent(3) and friends attempt to read passwd/master.passwd from the disk, which obviously hung due to the SCSI controller. Therefore, one cannot log in and run any commands. > If the serial port is dead, you will probably still find you can get > output from the serial port, so start "date; vmstat -i" in a loop over > the serial port before it hangs, and watch the output once it wedges. Once the machine is hung like described, since running shell commands (date/vmstat/even spawning sh itself) involves disk I/O, this won't work. If date and vmstat could be cached in memory somewhere, this might work, but I don't know how one would do that. (A memory filesystem could work, but pretty much all of / would have to be there for this to work...) The best I could do would be to have a cronjob or a process running in a screen session which does date && vmstat -i over and over to a log file, and examine that log once the machine hung like described. This wouldn't tell us if the numbers were increasing/fluxuating *after* the hang, though. :-( -- | Jeremy Chadwick jdc at parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP: 4BD6C0CB |
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20070102180438.GA81454>