Weighted Real Servers; Health Check - Avaya P333R-LB User Manual

Chapter 9 Application Redirection
However, the list of cache servers is not restored to its original configuration. As a
result, persistency is only partially recovered.

Weighted Real Servers

You can assign weights to Real Servers (caches) to enable faster servers to receive a
larger share of sessions. This minimizes overloading and maximizes functionality
If you assign a weight to a Real Server, the sessions are distributed to the servers in
the same metric chosen (Hash or MinMiss Hash). However, weighted servers are
assigned a larger share of sessions. For example, if you assign a weight of 100 to one
and do not assign a weight to a second server, the weighted server receives 10
sessions for each session directed to the second server.

Health Check

The P333R-LB constantly health-checks the Real Servers to ensure that each Real
Server (in this case, each cache server) is accessible and operational. A cache server
that fails the health check is automatically removed from the load balancer's
internal list of currently available cache servers.
There are several types of health-check methods that the P333R-LB uses, among
them:
• ICMP Echo - Each cache is periodically pinged and checked if an answer was
received.
• TCP Port Checking - A TCP connection is periodically opened to every cache,
checking for successful completion of the connection.
240 Avaya P333R-LB User's Guide