Systemd/man/coredump.conf.xml
Zbigniew Jędrzejewski-Szmek fc6cec8613 coredump: remove Storage=both option
Back when external storage was initially added in 34c10968cb, this mode of
storage was added. This could have made some sense back when XZ compression was
used, and an uncompressed core on disk could be used as short-lived cache file
which does require costly decompression. But now fast LZ4 compression is used
(by default) both internally and externally, so we have duplicated storage,
using the same compression and same default maximum core size in both cases,
but with different expiration lifetimes. Even the uncompressed-external,
compressed-internal mode is not very useful: for small files, decompression
with LZ4 is fast enough not to matter, and for large files, decompression is
still relatively fast, but the disk-usage penalty is very big.

An additional problem with the two modes of storage is that it complicates
the code and makes it much harder to return a useful error message to the user
if we cannot find the core file, since if we cannot find the file we have to
check the internal storage first.

This patch drops "both" storage mode. Effectively this means that if somebody
configured coredump this way, they will get a warning about an unsupported
value for Storage, and the default of "external" will be used.
I'm pretty sure that this mode is very rarely used anyway.
2016-09-28 23:49:01 +02:00

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<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!--
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Copyright 2014 Zbigniew Jędrzejewski-Szmek
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You should have received a copy of the GNU Lesser General Public License
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-->
<refentry id="coredump.conf" conditional="ENABLE_COREDUMP"
xmlns:xi="http://www.w3.org/2001/XInclude">
<refentryinfo>
<title>coredump.conf</title>
<productname>systemd</productname>
<authorgroup>
<author>
<contrib>Developer</contrib>
<firstname>Lennart</firstname>
<surname>Poettering</surname>
<email>lennart@poettering.net</email>
</author>
</authorgroup>
</refentryinfo>
<refmeta>
<refentrytitle>coredump.conf</refentrytitle>
<manvolnum>5</manvolnum>
</refmeta>
<refnamediv>
<refname>coredump.conf</refname>
<refname>coredump.conf.d</refname>
<refpurpose>Core dump storage configuration files</refpurpose>
</refnamediv>
<refsynopsisdiv>
<para><filename>/etc/systemd/coredump.conf</filename></para>
<para><filename>/etc/systemd/coredump.conf.d/*.conf</filename></para>
<para><filename>/run/systemd/coredump.conf.d/*.conf</filename></para>
<para><filename>/usr/lib/systemd/coredump.conf.d/*.conf</filename></para>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>These files configure the behavior of
<citerefentry><refentrytitle>systemd-coredump</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
a handler for core dumps invoked by the kernel. Whether <command>systemd-coredump</command> is used
is determined by the kernel's
<varname>kernel.core_pattern</varname> <citerefentry project='man-pages'><refentrytitle>sysctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>
setting. See
<citerefentry><refentrytitle>systemd-coredump</refentrytitle><manvolnum>8</manvolnum></citerefentry>
and
<citerefentry project='man-pages'><refentrytitle>core</refentrytitle><manvolnum>5</manvolnum></citerefentry>
pages for the details.</para>
</refsect1>
<xi:include href="standard-conf.xml" xpointer="main-conf" />
<refsect1>
<title>Options</title>
<para>All options are configured in the
<literal>[Coredump]</literal> section:</para>
<variablelist>
<varlistentry>
<term><varname>Storage=</varname></term>
<listitem><para>Controls where to store cores. One of <literal>none</literal>,
<literal>external</literal>, and <literal>journal</literal>. When
<literal>none</literal>, the core dumps will be logged (included the traceback if
possible), but not stored permanently. When <literal>external</literal> (the
default), cores will be stored in <filename>/var/lib/systemd/coredump/</filename>.
When <literal>journal</literal>, cores will be stored in the journal and rotated
following normal journal rotation patterns.</para>
<para>When cores are stored in the journal, they might be
compressed following journal compression settings, see
<citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
When cores are stored externally, they will be compressed
by default, see below.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>Compress=</varname></term>
<listitem><para>Controls compression for external
storage. Takes a boolean argument, which defaults to
<literal>yes</literal>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><varname>ProcessSizeMax=</varname></term>
<listitem><para>The maximum size in bytes of a core
which will be processed. Core dumps exceeding this size
will be logged, but the backtrace will not be generated
and the core will not be stored.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>ExternalSizeMax=</varname></term>
<term><varname>JournalSizeMax=</varname></term>
<listitem><para>The maximum (uncompressed) size in bytes of a
core to be saved.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>MaxUse=</varname></term>
<term><varname>KeepFree=</varname></term>
<listitem><para>Enforce limits on the disk space taken up by
externally stored core dumps. <option>MaxUse=</option> makes
sure that old core dumps are removed as soon as the total disk
space taken up by core dumps grows beyond this limit (defaults
to 10% of the total disk size). <option>KeepFree=</option>
controls how much disk space to keep free at least (defaults
to 15% of the total disk size). Note that the disk space used
by core dumps might temporarily exceed these limits while
core dumps are processed. Note that old core dumps are also
removed based on time via
<citerefentry><refentrytitle>systemd-tmpfiles</refentrytitle><manvolnum>8</manvolnum></citerefentry>. Set
either value to 0 to turn off size-based
clean-up.</para></listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
<citerefentry><refentrytitle>coredumpctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd-tmpfiles</refentrytitle><manvolnum>8</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>