cf_catchup_trgt - Target for catch up time of secondary cluster caching facility configuration parameter
This configuration parameter determines the target time in minutes for completing the catch up to bring a newly added or newly restarted cluster caching facility into peer state with an existing primary cluster caching facility .
- Configuration type
- Database
- Parameter type
- Configurable online
- Default [range]
- 15 [ 1 - 600 ]
- Unit of measure
- Minutes since the secondary cluster caching facility was started
This parameter sets a target time for members to bring a newly added secondary cluster caching facility into peer state with the primary cluster caching facility.
Once it is in peer state, the secondary cluster caching facility is able to take over the role of the primary cluster caching facility if the primary cluster caching facility fails or is shut down for maintenance.
A lower setting for cf_catchup_trgt causes members to aggressively
perform catch up activity, thus minimizing the window during which a Db2®
pureScale® instance
is running without a secondary cluster caching facility that is ready to take
over the role of the primary. A lower setting has a larger impact on database transactions and the
overall performance of the system since more system resources (for example, I/O bandwidth) are used
for catch up activity.
Note: Although the default setting for
cf_catchup_trgt balances system performance with high availability, the
following rule of thumb can be used to tune this parameter:
- If availability is more important than performance, use a lower setting for cf_catchup_trgt.
- If performance is more important than availability, use a higher setting for cf_catchup_trgt.