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Intermittent drop in free space in the root directory

Andrew Kaplan
Super Advisor

Intermittent drop in free space in the root directory

Hi there --

One of our systems, running HP-UX 11.11, experiences an intermittent drop in free space in its root directory. The problem normally goes away after ninety minutes.

What would be causing this issue, and is there anything that can or should be done to stop it?
A Journey In The Quest Of Knowledge
3 REPLIES
Pete Randall
Outstanding Contributor

Re: Intermittent drop in free space in the root directory

Andrew,

I would have to guess that some process is writing where it shouldn't - backup going /dev/rmt/Om (capital letter o rather than zero), for example. It should definitely be found and corrected but the only way to do that is to patiently watch for it to happen and then check what's running at the time. Look for cron jobs, too.


Pete

Pete
Rick Garland
Honored Contributor

Re: Intermittent drop in free space in the root directory

There are many reasons this can occur. Any NFS mounts hanging off the / mount point instead of a defined mount point? Are logs being written to root? This can include the /tmp as well, depends on how you set it up. The /var/adm area in for sys logs and if you did not create a separate mount point then you could have writes there as well. An application that runs for 90 minutes at a time is writing it output to the root?

As stated, there could be many reasons.
James R. Ferguson
Acclaimed Contributor

Re: Intermittent drop in free space in the root directory

Hi:

This would suggest that some process is writing a temporary file in the root directory.

A common technique is to open a file and immediately unlink() [remove] it. This prevents you from seeing the file in a directory listing but until the last process using the file terminates, the inode and allocated blocks of the file prevail. You can use 'lsof' to find the process(es) with open, unlinked files. For example:

# lsof +D /root +L1

...and look for any files with an NLINK value of zero (0). These are files with a zero link count that will vanish when the last process terminates. The SIZE/OFFSET column shows the character size of the file in question.

Regards!

...JRF...