Date: Fri, 26 Jun 2020 20:23:31 +1000 From: Peter Jeremy <peter@rulingia.com> To: Donald Wilde <dwilde1@gmail.com> Cc: Paul Mather <paul@gromit.dlib.vt.edu>, freebsd-stable <freebsd-stable@freebsd.org> Subject: Re: swap space issues Message-ID: <20200626102331.GA6406@server.rulingia.com> In-Reply-To: <CAEC7391AHKXd0KfJdUGKMv1QRh_AtA1BrtqaQwy3dXEoJEMoDw@mail.gmail.com> References: <CAEC7391qs%2BA-jMpR1RyvR-BmnLyiksXHkQUjsGeePuEZJfMciw@mail.gmail.com> <20200625000410.GA10210@eureka.lemis.com> <CAEC7390VDxbYSY%2B4_fEaYxwdSPzbFWUVTdHw=vbAgq%2Bnmv09Vw@mail.gmail.com> <20200625025248.GB10210@eureka.lemis.com> <CAEC73938Wjb5MHvLW36PdoAy_nso-tSN51AhUYydC6qxY99pog@mail.gmail.com> <E8763B97-2DB7-4C77-864D-08155168E352@gromit.dlib.vt.edu> <CAEC7391AHKXd0KfJdUGKMv1QRh_AtA1BrtqaQwy3dXEoJEMoDw@mail.gmail.com>
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--Qxx1br4bt0+wmkIi Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 2020-Jun-25 11:30:31 -0700, Donald Wilde <dwilde1@gmail.com> wrote: >Here's 'pstat -s' on the i3 (which registers as cpu HAMMER): > >Device 1K-blocks Used Avail Capacity >/dev/ada0s1b 33554432 0 33554432 0% >/dev/ada0s1d 33554432 0 33554432 0% >Total 67108864 0 67108864 0% I strongly suggest you don't have more than one swap device on spinning rust - the VM system will stripe I/O across the available devices and that will give particularly poor results when it has to seek between the partitions. Also, you can't actually use 64GB swap with 4GB RAM. If you look back through your boot messages, I expect you'll find messages like: warning: total configured swap (524288 pages) exceeds maximum recommended a= mount (498848 pages). warning: increase kern.maxswzone or reduce amount of swap. or maybe: WARNING: reducing swap size to maximum of xxxxMB per unit The absolute limit on swap space is vm.swap_maxpages pages but the realistic limit is about half that. By default the realistic limit is about 4=D7RAM = (on 64-bit architectures), but this can be adjusted via kern.maxswzone (which defines the #bytes of RAM to allocate to swzone structures - the actual space allocated is vm.swzone). As a further piece of arcana, vm.pageout_oom_seq is a count that controls the number of passes before the pageout daemon gives up and starts killing processes when it can't free up enough RAM. "out of swap space" messages generally mean that this number is too low, rather than there being a shortage of swap - particularly if your swap device is rather slow. --=20 Peter Jeremy --Qxx1br4bt0+wmkIi Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQKTBAEBCgB9FiEE2M6l8vfIeOACl4uUHZIUommfjLIFAl71zJVfFIAAAAAALgAo aXNzdWVyLWZwckBub3RhdGlvbnMub3BlbnBncC5maWZ0aGhvcnNlbWFuLm5ldEQ4 Q0VBNUYyRjdDODc4RTAwMjk3OEI5NDFEOTIxNEEyNjk5RjhDQjIACgkQHZIUommf jLIBGg/+M/QMpqdHrXkKWEseuc4T8URFNbrJJc/gIJGvUZ7d7yKawYRnZvdy3LcS AkCKFougUF5NEPa4XcDs/Mz1PRX0shaK3XWrXtaBLq4T+EwPNhNTrhzfTbzLjqEq O5sFxyutT4UenGUHUZafi6M/1M1OCFrmnwPFrorftC0uLgb04yhjCywzNNgmAeqv XtTdF7QguHDsD9Z5zIgqLqmaUl+pybiB2AOmUA9vnZM+XYJXxy5kXAH4fSaFof3Y UO32wTWEWvpNy6vIaQ6HsXYeLP6pzRQ8Lj05MchkCB/1ahhT2i8eEzSU3QiZcbJE 8kNzaQk0PzGLNmkHWRI4Sr/6mJiIWTmTco5v7ao7W/pwoYE4ILdrMzwDLZiZpx7G 9IAm0JKhufbxxiPLHNJWb0kNlWcHY6E7eltDneGPGM8h8yxyoHRkuTd35O0RCWBN Qgu+Rh1r4GJH1QoMJFFXkpr0uTnytT8h7oHF8b20evMD/8rn9VQL0oaQkN+G8t1+ S8PqskbWdH7capbdVzRALTuzA7LBcTyMx4jk/btdv8uCZFPFoD/apsmulgLlBSDL OdOkFkPTS8ahTVS3zggyrVKmFmBG2dR8e3cwF9vrJ+oE95x6mBCq5tEHkQSSsZqS nmtQX41S+Wk++ueJQavaglBPi4h2ubTOdkhSw4+a3nkvsuwp/tE= =esio -----END PGP SIGNATURE----- --Qxx1br4bt0+wmkIi--
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