Date: Tue, 22 Jul 2014 15:22:14 -0400 From: Lowell Gilbert <freebsd-questions-local@be-well.ilk.org> To: Ralf Mardorf <ralf.mardorf@rocketmail.com> Cc: freebsd-questions@freebsd.org Subject: Re: [Bulk] Re: How much swap space for a 32 GB RAM system? Message-ID: <44k375w655.fsf@be-well.ilk.org> In-Reply-To: <1406052132.7452.7.camel@rocketmail.com> (Ralf Mardorf's message of "Tue, 22 Jul 2014 20:02:12 %2B0200") References: <53CE8BB8.7030303@qeng-ho.org> <53CE8F62.8090701@tysdomain.com> <lqm7dg$vau$1@ger.gmane.org> <1406052132.7452.7.camel@rocketmail.com>
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Ralf Mardorf <ralf.mardorf@rocketmail.com> writes: > On Tue, 2014-07-22 at 13:35 -0400, Michael Powell wrote: >> Since I don't use such things (me sysadmin - not a coder) I'm not as >> knowledgeable, but I seem to recall that a crash dump needs a swap >> that is as large as physical memory. > > "My 48GB swap file system isn't fully recognized. > Q. What is the max amount of swap a system can use? > A. Are you sure you want/need that much swap anyway? The old-school 2-4x > RAM doesn't really apply, though you may want a bit more than 1x > physical RAM if you are capturing a crash dump, and some systems have >>32GB RAM now. Swap can be limited by kern.maxswzone which controls the > size of metadata use to track swap (8.X default is 64MB allowing ~15GB > of swap). Note other changes are required to have >8x physical RAM for > swap." - https://commons.lbl.gov/display/~jwelcher@lbl.gov/FreeBSD > +Random+FAQ That's a little out of date, because crash dumps now default to a minidump and take much less space. You're unlikely to want a full dump and can always add a new disk for the purpose if you ever do. > Interesting thread, since there isn't an answer for Linux and I plan to > use a new FreeBSD install in the close future too. Fair enough. There's always advice to be found, but "how much swap" in a vastly less interesting or consequential question than it used to be.
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