Attachment 47946 Details for Bug 113609

How to debug system initialisation

README.Logging (text/plain), 2.88 KB, created by Christian Zoz on 2005-08-29 10:06:12 UTC

(hide)

Description:

Filename:

MIME Type:

Creator: Christian Zoz

Created: 2005-08-29 10:06:12 UTC

Size: 2.88 KB

patch

obsolete

>How to watch udev activity when booting
>#######################################
>
>
>1) Make syslog start before udev:
>^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>Since udev writes all output to syslog, we need service syslog running before
>udevd starts. There are two ways to achieve this.
>
>Either add the needed link to /etc/init.d/earlysyslog in /etc/init.d/boot.d/ manually. But it must start later then boot.rootfsck.
>
>Or you edit the service scripts itself and let insserv create the links. You
>have to change earlysyslog and boot.udev:
>  /etc/init.d/earlysyslog
>    Add 'B' to 'Default-Start:' and 'boot.rootfsck' to 'Required-Start:'
>    # Required-Start: boot.rootfsck
>    # Default-Start:  B 2 3 5
>  /etc/init.d/boot.udev
>    Add 'earlysyslog' to 'Required-Start'
>    # Required-Start:    boot.rootfsck earlysyslog
>Then call
>  /sbin/insserv -d earlysyslog
>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.
>
>
>Have a lot of fun, as always ;)
>

Actions: View

Attachments on bug 113609: 47946 | 47947 | 48107