The maximum size of the configuration file that can be loaded into an IP500 V2 control unit is 2.0 MB. When you attempt to save a configuration that is too large, you are warned and the save canceled.

During normal operation, additional configuration records can be added to the configuration without using Manager (for example directory records made from phones). If, during the overnight backup to flash memory, the configuration if found to be too large, records are removed until the configuration is sufficiently small to be backed up. The  records removed are system directory records and then personal directory in that order.

Note that those records will still exist in the configuration running the system in its RAM memory, however if the system is restarted they will disappear as the configuration is reloaded from the Flash memory.