IBM Support

Shell Commands may fail if /tmp is full

Troubleshooting


Problem

Some shell commands that need to write to /tmp in order to execute (such as $(id)) may fail without a message if /tmp is full.

Symptom

For Example: $(id) issued on a system where /tmp is defined as an HFS or ZFS and is full, will just return a blank line instead of the output from the id command. There is no error message produced. If the $(id) command is issued on a system where /tmp is defined as a TFS and is full, you will see the following error message:
FSUMF316 Cannot open temporary file /tmp/shbHHHcgFgA: EDC5133I No space left on device.

In addition, see Info APAR II13317 for more information on /tmp full issues.

Cause

This error is caused because some shell commands need to write to /tmp in order to execute.

Environment

z/OS

Diagnosing The Problem

If you see the above symptoms (either the FSUM error message, or no output from the shell command you are issuing, check to see if /tmp is full by issuing the following command:

df /SYSTEM/tmp

Resolving The Problem

If you find /tmp with 0 Available Space, free some space and try the command again.

Some tools you can use to prevent a full /tmp are as follows:

1)  fsfull mount parameter  For example:  you would see message IGW023A when the file system is 70 percent full. Then it would issue another message when the file system is 80 and 90 percent full when this mount parameter is coded.  The 70,10 can be set according to your preference.


 mount parm('FSFULL(70,10)')

2) zFS aggrfull (default OFF) mount parameter can be turned ON to specify the threshold and increment for reporting aggregate full error messages to the operator.

3) The skulker shell command was created for the purpose of cleaning up old files (/tmp/).  In addition, the skulker tool can be used with a cron job to periodically clean out old /tmp/ files.

4) TMPDIR - You can reduce /tmp activity by setting the TMPDIR environment variable to $HOME/tmp in each user's .profile.  This action causes various utilities to put temporary files in the user's $HOME/tmp directory rather than in the common /tmp directory.  If TMPDIR is not set, the z/OS shell uses /tmp.  

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Document Information

More support for:
z/OS

Software version:
1.13, 2.1, 2.2

Operating system(s):
z/OS

Document number:
669957

Modified date:
03 September 2021

UID

isg3T1010626

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