To determine how efficiently the database server uses memory, use the information about memory segment usage that you collect in your performance history from onstat -g seg output. Adjust the size of the virtual and resident portions of shared memory according to the following guidelines:
If many segments are dynamically added in the V class, multiply the average number of added virtual segments by the amount specified by the SHMADD configuration parameter. Then increase the value specified by the SHMVIRTSIZE configuration parameter by this amount.
Each block of memory is eight kilobytes in size. If the blkfree column contains many segments with a V class, reduce the size of the virtual segment of memory by eight times the average number of blkfree entries. You can then increase the size of the resident portion of memory accordingly.