[Novalug] /var log and other partitions

[The Doctor]

maxpublic08 at maxwellspangler.com wrote:

>> Assuming that /var resides in its own partition, what happens if it fills
>> up? What are the consequences to the system, will it still be online
>> but the
>> daemons/services would crash?
> 
> My guess is that most programs would continue to operate.  They should
> be setup to attempt to write to log files but failure to write to a log
> file is not critical for most programs and they should simply move on to
> their real work.

I ran into this a couple of days ago with my mail server - a quarantine
maildir filled up the /var partition to 100% of capacity.

System: Gentoo Linux 2007.0.

Setup: net-qmail, qmail-scanner, spamassassin.

What happened was this: Logging stopped because there was nowhere for
syslog-ng to write to.  Logfile rotation stopped.  Queuing of messages
stopped.  Scanning of messages stopped.  I wasn't able to gracefully
shut the system down because there was nowhere for the shutdown.pid file
to be written to.  I wasn't able to gracefully shut down a couple of
other things either, for the same reason.  What I wound up doing was
killing most of the running daemons manually and erasing old logs under
/var/log to free up some disk space.  Once that was done I was able to
reboot into single user mode and start erasing the junk under
/var/spool/qmailscan/quarantine/new.  After another reboot everything
started operating normally again.

> A minimum so that if filesystem containing data for running programs
> fills up and can't be written to, space should still be available to log
> the problem on a /var/log file.

Under certain circumstances, it might be advisable to break /var/log out
into its own partition, but usually it isn't.

-- 

The Doctor [412/724/301/703]

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