This variable is new in 5.0.13, 6.0.4 and 6.5.4
SPR# RGET5K627Q - This fix reduces the likelihood of duplicate partition
numbers used in IPC keys on Unix, and provides a Notes.ini parameter,
"PARTITION_KEYNUMBER", to handle any remnant collisions. This regression was
introduced in 5.0.7 and has been fixed in 5.0.13, 6.0.5, and 6.5.4.
None, although you can specify this setting in the NOTES.INI Settings tab of
the Configuration Settings document in the Domino Directory.
Lotus Notes/Domino 5.0.13
Lotus Notes/Domino x.x.x