1SYSTEMD-PSTORE.SERVICE(8)   systemd-pstore.service   SYSTEMD-PSTORE.SERVICE(8)
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NAME

6       systemd-pstore.service, systemd-pstore - A service to archive contents
7       of pstore
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SYNOPSIS

10       /usr/lib/systemd/systemd-pstore
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12       systemd-pstore.service
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DESCRIPTION

15       systemd-pstore.service is a system service that archives the contents
16       of the Linux persistent storage filesystem, pstore, to other storage,
17       thus preserving the existing information contained in the pstore, and
18       clearing pstore storage for future error events.
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20       Linux provides a persistent storage file system, pstore, that can store
21       error records when the kernel dies (or reboots or powers-off). These
22       records in turn can be referenced to debug kernel problems (currently
23       the kernel stores the tail of the kernel log, which also contains a
24       stack backtrace, into pstore).
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26       The pstore file system supports a variety of backends that map onto
27       persistent storage, such as the ACPI ERST and UEFI variables. The
28       pstore backends typically offer a relatively small amount of persistent
29       storage, e.g. 64KiB, which can quickly fill up and thus prevent
30       subsequent kernel crashes from recording errors. Thus there is a need
31       to monitor and extract the pstore contents so that future kernel
32       problems can also record information in the pstore.
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34       The pstore service is independent of the kdump service. In cloud
35       environments specifically, host and guest filesystems are on remote
36       filesystems (e.g. iSCSI or NFS), thus kdump relies (implicitly and/or
37       explicitly) upon proper operation of networking software *and* hardware
38       *and* infrastructure. Thus it may not be possible to capture a kernel
39       coredump to a file since writes over the network may not be possible.
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41       The pstore backend, on the other hand, is completely local and provides
42       a path to store error records which will survive a reboot and aid in
43       post-mortem debugging.
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45       The systemd-pstore executable does the actual work. Upon starting, the
46       pstore.conf file is read and the /sys/fs/pstore/ directory contents are
47       processed according to the options. Pstore files are written to the
48       journal, and optionally saved into /var/lib/systemd/pstore/.
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CONFIGURATION

51       The behavior of systemd-pstore is configured through the configuration
52       file /etc/systemd/pstore.conf and corresponding snippets
53       /etc/systemd/pstore.conf.d/*.conf, see pstore.conf(5).
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55   Disabling pstore processing
56       To disable pstore processing by systemd-pstore, set
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58           Storage=none
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60       in pstore.conf(5).
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62   Kernel parameters
63       The kernel has two parameters,
64       /sys/module/kernel/parameters/crash_kexec_post_notifiers and
65       /sys/module/printk/parameters/always_kmsg_dump, that control writes
66       into pstore. The first enables storing of the kernel log (including
67       stack trace) into pstore upon a panic or crash, and the second enables
68       storing of the kernel log upon a normal shutdown (shutdown, reboot,
69       halt). These parameters can be managed via the tmpfiles.d(5) mechanism,
70       specifically the file /usr/lib/tmpfiles/systemd-pstore.conf.
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USAGE

73       Data stored in the journal can be viewed with journalctl(1) as usual.
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SEE ALSO

76       pstore.conf(5)
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80systemd 248                                          SYSTEMD-PSTORE.SERVICE(8)
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