Specifies the size to be reserved in each database block. RESERVED_BYTES is generally used to reserve room for compatibility with other implementations of M or to observe communications protocol restrictions. The format of the RESERVED_BYTES qualifier is:
-RES[ERVED_BYTES]=size
RESERVED_BYTES may also be used as a user-managed fill factor.
The minimum RESERVED_BYTES is 0 bytes. The maximum RESERVED_BYTES is the block size minus the size of the block header which is 7 or 8 depending on your platform. Realistic determinations of this amount should leave room for at least one record of maximum size.