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NAME | SYNOPSIS | DESCRIPTION | CONFIGURATION | USAGE | SEE ALSO | COLOPHON |
SYSTEMD-PSTORE.SERVICE(8) systemd-pstore.service SYSTEMD-PSTORE.SERVICE(8)
systemd-pstore.service, systemd-pstore - A service to archive
contents of pstore
/usr/lib/systemd/systemd-pstore
systemd-pstore.service
systemd-pstore.service 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.
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 stuffs the tail of the dmesg, which also
contains a stack backtrace, into pstore).
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.
The pstore service is independent of the kdump service. In cloud
environments specifically, host and guest filesystems are on remote
filesystems (eg. 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.
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.
The systemd-pstore executable does the actual work. Upon starting,
the pstore.conf file is read and the /sys/fs/pstore directory
contents are processed according to the options. Pstore files are
written to the journal, and optionally saved into
/var/lib/systemd/pstore.
The behavior of systemd-pstore is configured through the
configuration file /etc/systemd/pstore.conf and corresponding
snippets /etc/systemd/pstore.conf.d/*.conf, see pstore.conf(5).
Disabling pstore processing
To disable pstore processing by systemd-pstore, set
Storage=none
in pstore.conf(5).
Controlling kernel parameters
The kernel has two parameters,
/sys/module/kernel/parameters/crash_kexec_post_notifiers and
/sys/module/printk/parameters/always_kmsg_dump, that control writes
into pstore. The crash_kexec_post_notifiers parameter enables the
kernel to write dmesg (including stack trace) into pstore upon a
panic or crash, and printk.always_kmsg_dump parameter enables the
kernel to write dmesg upon a normal shutdown (shutdown, reboot,
halt). These kernel parameters are managed via the tmpfiles.d(5)
mechanism, specifically the file
/usr/lib/tmpfiles/systemd-pstore.conf.
Data stored in the journal can be viewed with journalctl(1) as usual.
pstore.conf(5)
This page is part of the systemd (systemd system and service manager)
project. Information about the project can be found at
⟨http://www.freedesktop.org/wiki/Software/systemd⟩. If you have a bug
report for this manual page, see
⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩. This
page was obtained from the project's upstream Git repository
⟨https://github.com/systemd/systemd.git⟩ on 2020-08-13. (At that
time, the date of the most recent commit that was found in the repos‐
itory was 2020-08-11.) If you discover any rendering problems in
this HTML version of the page, or you believe there is a better or
more up-to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not part
of the original manual page), send a mail to man-pages@man7.org
systemd 246 SYSTEMD-PSTORE.SERVICE(8)
Pages that refer to this page: pstore.conf(5) , pstore.conf.d(5) , 30-systemd-environment-d-generator(7) , systemd.index(7)