Replication Frequency - Cisco 2509 - Router - EN User Manual

CiscoSecure Database Replication

Replication Frequency

User Guide for Cisco Secure ACS for Windows Server
8-14
If server 2 were configured to replicate to server 1 in addition to receiving
replication from server 1, replication to server 2 would fail. Cisco Secure ACS
cannot support such a configuration, known as bidirectional replication. To
safeguard against this, a secondary Cisco Secure ACS aborts replication when its
primary Cisco Secure ACS appears on its Replication list.
Figure 8-1 Cascading Database Replication
Server 2
Server 1
Server 3
The frequency with which your Cisco Secure ACSes replicate can have important
implications for overall AAA performance. With shorter replication frequencies,
a secondary Cisco Secure ACS is more up-to-date with the primary
Cisco Secure ACS. This allows for a more current secondary Cisco Secure ACS
if the primary Cisco Secure ACS fails.
There is a cost to having frequent replications. The more frequent the replication,
the higher the load on a multi-server Cisco Secure ACS architecture and on your
network environment. If you schedule frequent replication, network traffic is
much higher. Also, processing load on the replicating systems is increased.
Replication consumes system resources and briefly interrupts authentication; thus
the more often replication is repeated, the greater the impact on the AAA
performance of the Cisco Secure ACS.
This issue is more apparent with databases that are large or that frequently change.
Database replication is a non-incremental, destructive backup. In other words, it
completely replaces the database and configuration on the secondary
Chapter 8 Establishing Cisco Secure ACS System Configuration
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