The default location of the temporary folder of the java machine is /tmp. AEM uses this folder too, for example when building packages.
If you want to change the location of the temporary folder (for example, if you need a directory with more free space) then define a <new-tmp-path> by adding the JVM parameter:
-Djava.io.tmpdir="/<new-tmp-path>"
to either:
- the server startup command line
- the CQ_JVM_OPTS environment parameter in the serverctl or start script
REFERENCES
[1] http://docs.adobe.com/docs/en/aem/6-0/deploy/custom-standalone-install.html