The CSALIMIT start option specifies the maximum amount of common service area (CSA) that is used by VTAM®. It can be used to prevent VTAM from using CSA that is needed by the operating system. Most environments do not need to limit VTAM use of CSA because their peak CSA usage is a very small increment over their requirements when all of their logical units are in session.

If the limit specified by CSALIMIT is reached, the results are unpredictable. If LPBUF cannot be expanded, VTAM might enter a deadlock condition. Therefore, if you specify the CSALIMIT start option, you should define LPBUF large enough so that it does not have to expand. Other possible occurrences are that messages can be lost or a session initiation or termination can fail. Coding a value for CSALIMIT without the ,F modifier can limit these exposures. See the z/OS Communications Server: SNA Resource Definition Reference for details.