May be, IBM Lotus Notes/Domino memory model specification.
Domino is first allocated memory is 2/5 available memory space.
when the Domino require more memory space, then inclement allocate memory from free memory space.
when the Domino useless these are memory, Domino allocated memory space do not relase when restart server.
causes of ‘task manager’ seems to high rate allocate memory.
this problem solves to periodically server restart.