mirror of
https://github.com/systemd/systemd.git
synced 2024-12-25 01:34:28 +03:00
115 lines
5.0 KiB
XML
115 lines
5.0 KiB
XML
<?xml version='1.0'?>
|
|
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
|
|
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
|
|
<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
|
|
|
|
<refentry id="systemd-pstore" conditional='ENABLE_PSTORE'
|
|
xmlns:xi="http://www.w3.org/2001/XInclude">
|
|
|
|
<refentryinfo>
|
|
<title>systemd-pstore.service</title>
|
|
<productname>systemd</productname>
|
|
</refentryinfo>
|
|
|
|
<refmeta>
|
|
<refentrytitle>systemd-pstore.service</refentrytitle>
|
|
<manvolnum>8</manvolnum>
|
|
</refmeta>
|
|
|
|
<refnamediv>
|
|
<refname>systemd-pstore.service</refname>
|
|
<refname>systemd-pstore</refname>
|
|
<refpurpose>A service to archive contents of pstore</refpurpose>
|
|
</refnamediv>
|
|
|
|
<refsynopsisdiv>
|
|
<para><filename>/usr/lib/systemd/systemd-pstore</filename></para>
|
|
<para><filename>systemd-pstore.service</filename></para>
|
|
</refsynopsisdiv>
|
|
|
|
<refsect1>
|
|
<title>Description</title>
|
|
<para><filename>systemd-pstore.service</filename> is a system service that archives the
|
|
contents of the Linux persistent storage filesystem, pstore, to other storage,
|
|
thus preserving the existing information contained in the pstore, and clearing
|
|
pstore storage for future error events.</para>
|
|
|
|
<para>Linux provides a persistent storage file system, pstore, that can store error records when the
|
|
kernel dies (or reboots or powers-off). These records in turn can be referenced to debug kernel problems
|
|
(currently the kernel stores the tail of the kernel log, which also contains a stack backtrace, into
|
|
pstore).</para>
|
|
|
|
<para>The pstore file system supports a variety of backends that map onto persistent
|
|
storage, such as the ACPI ERST and UEFI variables. The pstore backends
|
|
typically offer a relatively small amount of persistent storage, e.g. 64KiB,
|
|
which can quickly fill up and thus prevent subsequent kernel crashes from
|
|
recording errors. Thus there is a need to monitor and extract the pstore
|
|
contents so that future kernel problems can also record information in the
|
|
pstore.</para>
|
|
|
|
<para>The pstore service is independent of the kdump service. In cloud environments
|
|
specifically, host and guest filesystems are on remote filesystems (e.g. iSCSI
|
|
or NFS), thus kdump relies (implicitly and/or explicitly) upon proper operation
|
|
of networking software *and* hardware *and* infrastructure. Thus it may not be
|
|
possible to capture a kernel coredump to a file since writes over the network
|
|
may not be possible.</para>
|
|
|
|
<para>The pstore backend, on the other hand, is completely local and provides a path
|
|
to store error records which will survive a reboot and aid in post-mortem
|
|
debugging.</para>
|
|
|
|
<para>The <command>systemd-pstore</command> executable does the actual work. Upon starting,
|
|
the <filename>pstore.conf</filename> file is read and the <filename>/sys/fs/pstore/</filename>
|
|
directory contents are processed according to the options. Pstore files are written to the
|
|
journal, and optionally saved into <filename>/var/lib/systemd/pstore/</filename>.</para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Configuration</title>
|
|
|
|
<para>The behavior of <command>systemd-pstore</command> is configured through the configuration file
|
|
<filename>/etc/systemd/pstore.conf</filename> and corresponding snippets
|
|
<filename>/etc/systemd/pstore.conf.d/*.conf</filename>, see
|
|
<citerefentry><refentrytitle>pstore.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
|
|
</para>
|
|
|
|
<refsect2>
|
|
<title>Disabling pstore processing</title>
|
|
|
|
<para>To disable pstore processing by <command>systemd-pstore</command>,
|
|
set <programlisting>Storage=none</programlisting> in
|
|
<citerefentry><refentrytitle>pstore.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
|
|
</para>
|
|
</refsect2>
|
|
|
|
<refsect2>
|
|
<title>Kernel parameters</title>
|
|
|
|
<para> The kernel has two parameters,
|
|
<filename>/sys/module/kernel/parameters/crash_kexec_post_notifiers</filename> and
|
|
<filename>/sys/module/printk/parameters/always_kmsg_dump</filename>, that control writes into pstore.
|
|
The first enables storing of the kernel log (including stack trace) into pstore upon a panic or crash,
|
|
and the second enables storing of the kernel log upon a normal shutdown (shutdown, reboot, halt). These
|
|
parameters can be managed via the
|
|
<citerefentry><refentrytitle>tmpfiles.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>
|
|
mechanism, specifically the file <filename>/usr/lib/tmpfiles/systemd-pstore.conf</filename>.
|
|
</para>
|
|
</refsect2>
|
|
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Usage</title>
|
|
<para>Data stored in the journal can be viewed with
|
|
<citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
|
|
as usual.</para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>See Also</title>
|
|
<para>
|
|
<citerefentry><refentrytitle>pstore.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
|
|
</para>
|
|
</refsect1>
|
|
</refentry>
|