This object is used to specify the persistence of this
conceptual row in the 'xcmGenNotifyRuleTable' (and associated
conceptual rows in the 'xcmGenNotifyRuleDetailTable').
Usage: Dynamically created rows SHALL be given 'volatile'
or 'nonvolatile' persistence.
Usage: Conforming management agents SHALL NOT accept sets to
'xcmGenNotifyRuleRowPersistence'
AFTER row creation (this object is 'write-once').
Usage: Conforming management agents SHALL support
'volatile' (lost across power cycles), but NEED NOT support any
other levels of persistence.