Handful of general system errors in the log file and some hangs

Problem Description:

Suppose you have a jasperserver instance which has been running fine for many months.  Suddenly, you get hangs on doing some normal operations in the repository.  Or, it is getting exceedingly slow.    If you restart the system, it works fine for a while, then it slows down again.  You cannot identify a specific operation or specific report that is causing the problem.   There were no changes to the system recently.

Solution:

Since the system has been running fine for a long time and there were no changes recently, although you may not get a specific message, the problem could be out of disc space.  The biggest clue is probably the number of general non-specific errors rather than a single point failure error.  You can check disc space quickly by issuing the df command on Linux, or just check the drive storage property in Windows.  If your jasperserver is up, you can also run the diagnostic report in public/diagnostics to see how much disc space you have.  You can also check -Xmx to see if you are also low on heap memory.  

There could be other reasons for the failure, this is an easy one that should be eliminated quickly.