Attachment 46628 Details for Bug 105598

A tiny hotplug logging howto

Logging (text/plain), 2.23 KB, created by Christian Zoz on 2005-08-19 06:33:49 UTC

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Creator: Christian Zoz

Created: 2005-08-19 06:33:49 UTC

Size: 2.23 KB

patch

obsolete

>How to watch udev activity when booting
>#######################################
>
>
>1) Make syslog start before udev:
>^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>add 'B' to Default-Start: in /etc/init.d/earlysyslog
>call /sbin/insserv
>check if earlysyslog comes before boot.udev in /etc/init.d/boot.d/S*
>
>You need /var on your root partition for that because boot.localfs is started
>after udev. If you have a seperate /var partition, make it available somehow or
>change the location of your syslog file.
>
>
>2) Enable logging
>^^^^^^^^^^^^^^^^^
>set udev_log=info in /etc/udev/udev.conf. 
>
>There is also debug, but you are very
>probably not interested in the huge amount of debugging output from udev. It
>writes about 70M logfile at a single boot.
>
>Many tools which are called from hotplug also respect the setting of udev_log.
>But there might be some which need special actions to make them verbose.
>[to be enhanced: list tools and their individual debug switches]
>
>You may change udevs loglevel at runtime with
>  udevcontrol log_priority=<level>
>
>
>3) Reboot
>^^^^^^^^^
>For further processing of the logging output you should get a clean logfile at
>next boot. Just move the old logfile away. Syslog will still use the moved file
>until shutdown (until syslog restarted).
>mv /var/log/messages /var/log/messages.`date +%s`
>
>Then reboot.
>
>
>4) Getting logged events sorted
>^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>There is a script 'show_event_log' which may be used to extract info out of
>/var/log/messages. Call it
>  show_event_log <first> [<last> [<list of event types>] ]
><first> is the sequence number of the first event you are interested in.
><last>  is the number of the last event. You may write 'last' literally. It may
>        also be omitted if you want to see a single event. 
><list>  is a list of event types you like to see. If you omit it, you get most
>        events, not all. Some are exclude by default. Use " " as list if you
>	want to see really all. Or edit the list of skipped events in the first
>        lines of the script
>If you don't use /var/log/messages as lockfile you may set the environment
>variable MESSAGES=<logfile>.
>
>The script is slowly. It is just a quick hack. The larger the syslog file the
>slower the script. Therefore always boot with a fresh logfile.
>Improvements are welcome.

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