Date: Thu, 12 Jul 2018 08:50:08 -0600 From: Alan Somers <asomers@freebsd.org> To: Mark Johnston <markj@freebsd.org> Cc: Alexander Leidinger <Alexander@leidinger.net>, "freebsd-hackers@freebsd.org" <hackers@freebsd.org> Subject: Re: crashinfo doesn't support compressed crashdumps - which way forward? Message-ID: <CAOtMX2g6NsL9uMv8bf=QzkvWZ5EBSDK_=xbbkJqi%2BRK7afkRQQ@mail.gmail.com> In-Reply-To: <20180712143118.GA15892@raichu> References: <20180712141409.Horde.NVSzLsvqE-2PCSDqhhfb0Xd@webmail.leidinger.net> <20180712143118.GA15892@raichu>
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On Thu, Jul 12, 2018 at 8:31 AM, Mark Johnston <markj@freebsd.org> wrote: > On Thu, Jul 12, 2018 at 02:14:09PM +0200, Alexander Leidinger wrote: > > Hi, > > > > the crashinfo script doesn't know how to handle compressed coredumps. > > What would be acceptable behavior (ordered by my preferrence)? > > 1) decompress in /var/crash and then proceed normally (already > > implemented locally) > > 2) decompress to CRASHTMPDIR:/var/tmp/xxx and delete when finished > > 3) keep it like it is > > 4) teach tools to understand compressed dumps (gzip / zstd) > I briefly looked into this option, but it's harder than it sounds. There are several libraries that would need to be modified, and I think some of them work by mmap(2)ping the core file rather than by fread(2)ing it. I don't know of anyway to mmap a compressed file. > > > > Implicitly there is the question what what is the purpose of > > compressing crashdumps, to have more RAM than space in dumpdev (which > > is valid in my case), or to save space in /var/crash (which I don't > > care much about). > Compressed crashdumps are also great for systems with slow dumpdevs. They greatly speed up the dumping process. > > I think jhb has a patch which implements 2). I do not have strong > feelings on which is the right way forward, but I mildly prefer 2) to > 1). It looks like crashinfo can be disabled in rc.conf, so users who > are space-constrained in /var/crash can take the additional step of > setting crashinfo_enable=NO. FWIW, when I committed the compression > support, my use-case involved both a small dump device and a small > /var filesystem. > _______________________________________________ > freebsd-hackers@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-hackers > To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org" >
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