Date: Fri, 14 Apr 2017 13:39:44 -0700 From: "Ngie Cooper (yaneurabeya)" <yaneurabeya@gmail.com> To: Larry Rosenman <ler@lerctr.org> Cc: Slawa Olhovchenkov <slw@zxy.spb.ru>, "svn-src-head@freebsd.org" <svn-src-head@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, "src-committers@freebsd.org" <src-committers@freebsd.org>, Ngie Cooper <ngie@freebsd.org>, Alan Somers <asomers@freebsd.org> Subject: Re: svn commit: r316938 - head/sbin/savecore Message-ID: <12820BAB-D8BA-4EDE-89BC-4BDB56B1E57A@gmail.com> In-Reply-To: <A0AA951D-6F45-46E3-8B95-4254AA7899E6@lerctr.org> References: <201704141941.v3EJfmCW003347@repo.freebsd.org> <CAOtMX2gPHWRGiE9UA5AevZz=cTv_qksAWX0H-xRjDEHp0huCVg@mail.gmail.com> <20170414201431.GF20974@zxy.spb.ru> <CEC6CDCF-2EF2-4CEF-BF54-91F3021EF262@gmail.com> <0CAE4B1C-228B-4C71-86E9-4337753DFF74@lerctr.org> <EC89EB67-7854-4DE6-BD40-2626FF993181@gmail.com> <A0AA951D-6F45-46E3-8B95-4254AA7899E6@lerctr.org>
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--Apple-Mail=_215A0B22-5F85-4831-9C44-17E7863F09D3 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 > On Apr 14, 2017, at 13:37, Larry Rosenman <ler@lerctr.org> wrote: >=20 > On 4/14/17, 3:33 PM, "Ngie Cooper (yaneurabeya)" = <yaneurabeya@gmail.com> wrote: >=20 >> On Apr 14, 2017, at 13:26, Larry Rosenman <ler@lerctr.org> wrote: >>=20 >> On 4/14/17, 3:19 PM, "Ngie Cooper (yaneurabeya)" = <owner-svn-src-all@freebsd.org on behalf of yaneurabeya@gmail.com> = wrote: >>=20 >>> On Apr 14, 2017, at 13:14, Slawa Olhovchenkov <slw@zxy.spb.ru> = wrote: >>>=20 >>> On Fri, Apr 14, 2017 at 01:49:51PM -0600, Alan Somers wrote: >>>=20 >>>> On Fri, Apr 14, 2017 at 1:41 PM, Ngie Cooper <ngie@freebsd.org> = wrote: >>>>> Author: ngie >>>>> Date: Fri Apr 14 19:41:48 2017 >>>>> New Revision: 316938 >>>>> URL: https://svnweb.freebsd.org/changeset/base/316938 >>>>>=20 >>>>> Log: >>>>> savecore: fix space calculation with respect to `minfree` in = check_space(..) >>>>>=20 >>>>> - Use strtoll(3) instead of atoi(3), because atoi(3) limits the >>>>> representable data to INT_MAX. Check the values received from >>>>> strtoll(3), trimming trailing whitespace off the end to maintain >>>>> POLA. >>>>> - Use `KiB` instead of `kB` when describing free space, total = space, >>>>> etc. I am now fully aware of `KiB` being the IEC standard for = 1024 >>>>> bytes and `kB` being the IEC standard for 1000 bytes. >>>>> - Store available number of KiB in `available` so it can be more >>>>> easily queried and compared to ensure that there are enough KiB = to >>>>> store the dump image on disk. >>>>> - Print out the reserved space on disk, per `minfree`, so = end-users >>>>> can troubleshoot why check_space(..) is reporting that there = isn't >>>>> enough free space. >>>>>=20 >>>>> MFC after: 7 weeks >>>>> Reviewed by: Anton Rang <rang@acm.com> (earlier diff), cem = (earlier diff) >>>>> Tested with: positive/negative cases (see review); make tinderbox >>>>> Sponsored by: Dell EMC Isilon >>>>> Differential Revision: D10379 >>>>=20 >>>> The free space calculation is still uselessly conservative, because = it >>>> doesn't account for the fact that core dumps will always be either >>>> spare or compressed. The result is that savecore will frequently >>>> refuse to save corefiles even when there's plenty of space. I >>>> proposed removing the space check altogether in >>>> https://reviews.freebsd.org/D2587. However, I agreed to wait until >>>> after the compressed core dump feature was merged, because then = mostly >>>> accurate space checks will be possible. AFAIK the compressed core >>>> dump feature still hasn't been finished. >>>=20 >>> Is posible (in the future) to use multiple swaps (on multiple disks) >>> for save core dumps? >>=20 >> Multiple swap devices is already handled by savecore(8), if one = uses fstab(5) or dumpon(8). Otherwise, you must invoke savecore(8) on = individual devices. >>=20 >> As far as saving to multiple disks is concerned, I would hope that = one is using a redundancy capable filesystem (zfs) or RAID-like = technology (gmirror, graid, LSI Fusion=E2=80=99s RAID product line) to = stripe and/or mirror the data across multiple disks. >=20 > =E2=80=A6 >=20 >> How do I use multiple devices to have the system dump on all of my = swap? I got a message about not enough space, but there (I think) was = enough between multiple drives=E2=80=A6. >=20 > Something like: >=20 > - Create a zpool > - Mount zpool to /crashdumps > - Change dumpdir in /etc/rc.conf to be /crashdumps, e.g., echo = =E2=80=98dumpdir=3D/crashdumps=E2=80=99 >=20 > ? > HTH, > -Ngie >=20 > PS The issue with lack of space might be the issue that Alan = brought up earlier with compressed dumps and overly conservative free = space checks, or it might be the fact that dumpdir (default: /var/crash) = is full. >=20 >=20 > I was talking about the actual crashdump to swap by the system. = /var/crash has 10T of space (my root pool). If your memory is bigger than your swap, you=E2=80=99re unfortunately = not able to save the mini dump if the size of the saved pages exceed the = space on swap. I think this is where markj=E2=80=99s compressed dumps = feature will come in handy. Thanks! -Ngie --Apple-Mail=_215A0B22-5F85-4831-9C44-17E7863F09D3 Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc Content-Description: Message signed with OpenPGP using GPGMail -----BEGIN PGP SIGNATURE----- Comment: GPGTools - https://gpgtools.org iQIcBAEBCgAGBQJY8TOQAAoJEPWDqSZpMIYVIckP/1/wc/m+cB8E/xrSul7Da/3t rEEac5Wd87AcepXrjWINm76mV4ptWr2Wxob/1JH7xBC0tw3Tv8FcqKhsPRKW6Pyu phufjxc3yy1KZCZWRPhz6SA1k3hD3Q6zfnXbtxy13YH8M7CpLb78ni/wSmhuEorD VjJgdijY5y19f3JTfhw/FU3+5OOR/n+0058o5cEKavIZ6VWZmG2iQ4iujx808xpm V5q4OOVGlNNWXGIxGWnvea98dITdVIJYnUbW0ENLRAnxEcsFg0S0TWDFbBQA9qeR L3Co0SCfQaOw+nnPY8u84aiPqhaefrVzcn5iUr+M4qU9v3WPupj3Z0j2A5ZMExR9 19UQm6Aofm0ZnS1/Gp+wi7XLbMfxkhsVxlljLpRBR5q4KtWwttFwZijnLvdlYw0v zLiJqu0jCW5ZA+U3qKIXlU4uIqSmLj9iZEETA2/6J4SvcllMRI+raHgugIbHSBEl UlqFC/p40ByArQvzU4xWb2Ll8VR6iaKSWledkukKpRruHc0JU0h7GmIW4qzx1HlF Fsp9fzcTL1nAGJfqy3CW1SaBQ8d+kaw/9zLGSSRpzHkF6FUYl20+TWIxiB1luB3y 8UcYFNJdYh5NjXv2gybPvjogueU48ZceBQ9t3UM1ZKDvKSt2Tb/kzpGiXP5kf45t /Xw83eOleAC2Tq3Egj/t =288l -----END PGP SIGNATURE----- --Apple-Mail=_215A0B22-5F85-4831-9C44-17E7863F09D3--
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