Dynamic Intimate Shared Memory (DISM)

Dynamic Intimate Shared Memory (DISM) allows a database to dynamically extend or reduce the size of the shared data segment. This feature eliminates the misconfiguration problem and denial-of-service security vulnerability of Intimate Shared Memory (ISM).

The ISM is a shared memory segment that consists of large locked memory pages. The ISM number of locked pages remains constant or unchanged. Dynamic ISM (DISM) is pageable ISM shared memory, where the number of locked pages is variable or changeable. Therefore, the DISM supports releasing or adding more physical memory to the system during dynamic reconfiguration. The size of the DISM can span available physical memory plus disk swap.

See the man page shmop(2).

Large-page support is available for DISM in the Solaris 9 9/02 Update release. For a description of this large-page support, see SPARC: Dynamic Intimate Shared Memory (DISM) Large-Page Support.