Table 25-1 provides a comparison between the features of XRF and RSR.
XRF
RSR
Uses same physical log data sets and database data sets for active IMS and alternate IMS.
Uses completely separate log data sets and database data sets.
Active and alternate IMSs must be within the distance restrictions of the channel-to-channel connection between them.
Active and tracking systems are connected by network. Only limit on separation is network response.
Active IMS and alternate IMS must use IMS TM.
Active IMS can be any system updating IMS resources: DB/DC, TM only, DB only, or batch. The tracking IMS can be DB/DC or DBCTL.
One-to-one relationship between active IMS and alternate IMS.
One tracking IMS tracks many active IMSs.
All committed updates recorded on alternate IMS.
If there is a gap in the log data at the time of an unplanned takeover, any log data that comes after the gap is removed to ensure system integrity.
Switching to or from alternate IMS is comparatively simple.
Takeovers are more complex than for XRF.
Switch to alternate IMS takes one minute.
Switch to alternate takes less one hour.