commit ba5e4704a05cadfe4ccb478e06106d7e6240e53f parent 3357d21d7fb53237f1114d90623a9304b43306de Author: Daniel Barlow <dan@telent.net> Date: Wed, 18 Dec 2024 23:08:28 +0000 add short note about persistent logs Diffstat:
| M | doc/admin.rst | | | 20 | ++++++++++++++++++++ |
1 file changed, 20 insertions(+), 0 deletions(-)
diff --git a/doc/admin.rst b/doc/admin.rst @@ -131,6 +131,26 @@ human-readable format, use :command:`s6-tai64nlocal`. 1970-01-02 21:51:48.832588765 wan.link.pppoe sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x667a9594> <pcomp> <accom p>] +Log persistence +--------------- + +Logs written to :file:`/run/log/` will not survive a reboot or crash, +as it is an ephemeral filesystem. + +On supported hardware you can enable logging to `pstore +<https://www.kernel.org/doc/Documentation/ABI/testing/pstore>` which +means the most recent log messages will be preserved on reboot. +Set the config option ``logging.persistent.enable = true``, log messages will be written to :file:/dev/pmsg0. After rebooting, + +.. code-block:: console + + # mount -t pstore pstore /sys/fs/pstore/ + # ls -l /sys/fs/pstore/ + -r--r--r-- 1 43071 pmsg-ramoops-0 + # cat /sys/fs/pstore/pmsg-ramoops-0 + @40000000000000282c997d29 mydevice klogd <6>[ 30.793756] int: port 2(wlan0) entered blocking state + [log messages from before the reboot follow] + Updating an installed system (JFFS2)