Date: Wed, 22 Sep 2010 17:53:21 -0400 From: John Baldwin <jhb@freebsd.org> To: Ken Smith <kensmith@buffalo.edu> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, Gavin Atkinson <gavin@freebsd.org>, src-committers@freebsd.org, Andriy Gapon <avg@freebsd.org> Subject: Re: svn commit: r212964 - head/sys/kern Message-ID: <201009221753.21408.jhb@freebsd.org> In-Reply-To: <4C9A71ED.6020406@buffalo.edu> References: <201009211507.o8LF7iVv097676@svn.freebsd.org> <4C9A6EE6.5050301@freebsd.org> <4C9A71ED.6020406@buffalo.edu>
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On Wednesday, September 22, 2010 5:15:25 pm Ken Smith wrote: > On 9/22/10 5:02 PM, Andriy Gapon wrote: > > on 22/09/2010 22:58 John Baldwin said the following: > > > >> Agreed. FWIW, I actually think that this is the only change needed as > >> crashinfo is enabled by default in 8.x and later. We already include symbols > >> in kernels by default now, so just setting dumpdev will give you the same > >> info you generally can get from a textdump in the form of a simple > >> /var/crash/core.txt.N file. > >> > >> The other benefit of full crashdumps + crashinfo as compared to textdumps is > >> that a developer can request further information in a PR followup (fire up > >> kgdb and enter command 'X' and reply with the output). With a textdump any > >> info not collected by the textdump is lost once the machine reboots after the > >> crash. > > > > Agree++ > > But what was the reason that dumpdev="AUTO" was reverted? > > I remember that POLA was quoted at the time. > > I am not sure what the astonishment actually was - perhaps 'AUTO' was not smart > > enough and destroyed somebody's data? > > > > > Not everybody would notice /var getting full of crash dumps. > Picture a server farm where for the most part the machines > are all just plain on auto-pilot. If one or several develop > a problem that causes panic's /var can become full and possibly > cause the machine to stop doing something important (between > panic's...). I wasn't around when the initial decision for > what to have it set to was made but this was the reason for > me starting to do it again when I realized I forgot to at > least once, and hence the reference to POLA. > > Crash dumps are good for individual workstations. Crash > dumps are good for servers *if* the admin knows they're > having a problem and is actively working on that server > to resolve the issue. But they're no so good and can > cause nasty side-effects if they're happening on a machine > not being watched over closely. That's the reason for > the change in setting when a -stable branch gets started. FWIW, the Y! version of crashinfo auto-deletes crash dumps based on the available disk space for precisely this reason. With that addition crashinfo works quite well on a very large server farm. -- John Baldwin
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