Date: Mon, 24 Mar 2003 15:47:42 -0600 From: Mike Meyer <mwm-dated-1048974462.42fa56@mired.org> To: The Anarcat <anarcat@anarcat.ath.cx> Cc: freebsd-questions@freebsd.org Subject: Re: crashdumping on massive amounts of RAM Message-ID: <15999.31998.368285.164467@guru.mired.org> In-Reply-To: <20030324184555.GD831@lenny.anarcat.ath.cx> References: <20030324174332.GB831@lenny.anarcat.ath.cx> <15999.18326.297880.599596@guru.mired.org> <20030324184555.GD831@lenny.anarcat.ath.cx>
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In <20030324184555.GD831@lenny.anarcat.ath.cx>, The Anarcat <anarcat@anarcat.ath.cx> typed: > On Mon Mar 24, 2003 at 11:59:50AM -0600, Mike Meyer wrote: > > In <20030324174332.GB831@lenny.anarcat.ath.cx>, The Anarcat <anarcat@anarcat.ath.cx> typed: > > > I am fortunate enough to have a box with a lot (by my standards) of > > > RAM: > > > Any brilliant ideas to work around this? > > Yes - enable the kernel debugging option (DDB) on the kernel, and > > debug the running system when it panics. > The only problem I see with that is with non-reproducable panics, if I > don't debug *everything* properly the first time, I might not be able > to get back all the data I need. Yup, it's not as handy as having a dump. But dumps happen to swap, so you have to have a first swap partition that's at least 64K bigger than main memory. > > As for your swap partition - the same thing happens when you run out > > of virtual memory either way: processes start dieing. Having a little > > swap lets you get a warning of that because you'll start paging things > > out which would otherwise live in memory. Unless you're planning on > > setting up a warning system that watches for paging activity and > > notifies you so you can do something about it, there's probably not > > much point in having 250MB of swap on a system with a gigabyte of > > ram. In your shoes, I'd seriously consider running without swap. > I've considered it, but I found that I've been able to run over 1GB of > mem, so the 250MB is handy to handle exceptional situations as the > disk slows down allocation. If you've just run through a gigabyte of real ram, how long does an extra 250mb last you? > > On the other hand, disk space is so cheap that I always have lots of > > swap. Something about the days when I used to recompile LISP systems > > on memory-starved machines.... > Eh. It's a 40GB disk and I really considered putting 1GB of it for > swap. I've got a gigabyte of swap with only 20GB of real space. Of course, I use swap for /tmp with an mfs-backed file system. <mike -- Mike Meyer <mwm@mired.org> http://www.mired.org/consulting.html Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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