Indicates the file system volume number to which the
SVC billing usage data files will be written. The volume
number corresponds to the slot number on which the
volume resides.
Note: Value 0 has the special meaning that no
'Store' and 'Flush' operations will take
place. This translates to no Billing data
will be written to the local file system.
'Update' operations will still be performed on
each local slot. Full Billing statistics
will still be available in the wfFrSwUsageTable
MIB.