Date: Sat, 30 Mar 2002 17:17:49 -0800 From: Terry Lambert <tlambert2@mindspring.com> To: Dag-Erling Smorgrav <des@ofug.org> Cc: Poul-Henning Kamp <phk@critter.freebsd.dk>, arch@freebsd.org Subject: Re: Rewamping kernel dumps... Message-ID: <3CA663BD.A29AC43@mindspring.com> References: <35316.1017516515@critter.freebsd.dk> <xzpk7rtsi63.fsf@flood.ping.uio.no>
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Dag-Erling Smorgrav wrote: > Poul-Henning Kamp <phk@critter.freebsd.dk> writes: > > I would probably have stuck it all into tar(1) format from the > > beginning of the partition. One file for the msgbuf, one file for > > a ram snapshot etc etc. > > You can't put it at the beginning of the partition, because > savecore(8) can't run before fsck(8), and fsck(8) may cause the system > to swap and overwrite the core dump before savecore(8) has had a > chance to save it. You kind of want swapping to be enabled with swapon on all devices, rather than implicitly enabled on one device at boot time, so that unless you explicitly enable it, you do not have *any* swap available. IMO, fsck is just as likely to fail from a lack of 5 swap devices as it is to fail for lack of 1. The code needs to run in the available memory, rather than in more than the available memory. This would resolve the problem entirely. Also making FreeBSD able to run swap-less without a panic would clean up a couple other problems, which show up when you don't configure any swap at all, or show up exceedingly rarely and are impossible to really track down under swap exhaustion. Matt would be a good person to comment, at this point, since he has done a lot of work on how the system behaves under resource exhaustion conditions. -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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