A hang is passive if the top or vmstat 1 output show low CPU levels.
Possible causes of a passive hang include the following:
A deadlock resulting from locks or conditional variables
A defunct thread
On a Solaris system, collect several traces of the Directory Server process stack that is hanging, using the Solaris pstack utility. You must collect this information while the server is hanging. The consecutive pstack data should be collected every three seconds.
Collect several core files that show the state of the server threads while the server is hanging. Do this by generating a core file using the gcore command, changing the name of the core file, waiting 30 seconds, and generating another core file. Repeat the process as least once to get a minimum of three sets of core files and related data.
For more information about generating a core file, see Generating a Core File.