Date: Fri, 14 Apr 2017 15:26:20 -0500 From: Larry Rosenman <ler@lerctr.org> To: "Ngie Cooper (yaneurabeya)" <yaneurabeya@gmail.com>, Slawa Olhovchenkov <slw@zxy.spb.ru> Cc: "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: <0CAE4B1C-228B-4C71-86E9-4337753DFF74@lerctr.org> In-Reply-To: <CEC6CDCF-2EF2-4CEF-BF54-91F3021EF262@gmail.com> 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>
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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> wrot=
e:
>>> 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 spac=
e,
>>> etc. I am now fully aware of `KiB` being the IEC standard for 10=
24
>>> 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-user=
s
>>> 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 (earli=
er 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 most=
ly
>> 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 fs=
tab(5) or dumpon(8). Otherwise, you must invoke savecore(8) on individual de=
vices.
=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 (gmir=
ror, graid, LSI Fusion=E2=80=99s RAID product line) to stripe and/or mirror the da=
ta across multiple disks.
=20
Thanks!
-Ngie
=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 betwee=
n multiple drives=E2=80=A6.
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