5% of available system memory when first ISM segment is created.
0 to 50% of physical memory
None. Values that are too small can cause the system to hang or performance to severely degrade when memory is consumed with ISM segments.
On database servers with large amounts of physical memory using ISM, this parameter can be tuned downward. If ISM segments are not used, this parameter has no effect. A maximum value of 128 Mbytes (0x4000) is almost certainly sufficient on large memory machines.