Technical data

58 ServerIron ADX Advanced Server Load Balancing Guide
53-1002435-03
Other transparent cache switching options
2
Optionally, you can direct the ServerIron ADX to send client requests to another available cache
server in the same cache group that has not reached its maximum connection threshold without
changing the current hash distribution. Use the reselect-server-if-overloaded command under the
cache group configuration as shown in the following example.
ServerIronADX(config)# server cache-group 1
ServerIronADX(config-tc-1)# reselect-server-if-overloaded
Syntax: [no] reselect-server-if-overloaded
Setting cache server maximum TCP connection rates
You can modify the maximum connection rate for for individual TCP/UDP ports.
Configuring the connection rate control
Connection rate control enables you to limit the connection rate to a cache server. The ServerIron
ADX limits the number of new port connections per second to the number you specify.
The ServerIron ADX increments the connection counter for cache connections only after the
ServerIron ADX selects one for the connection. If the ServerIron ADX cannot serve a client request
because a cache already has the maximum number of connections for the current second for the
requested port, the ServerIron ADX tries another cache. If there are no caches available, the
ServerIron ADX directs the request to the Internet.
If you configure a limit for TCP and also for an individual application port, the ServerIron ADX uses
the lower limit. For example, if you limit new TCP connections to a real server to 1000 per second
and also limit new HTTP connections to 600 per second, the ServerIron ADX limits connections to
TCP port HTTP to 600 per second.
NOTE
The ServerIron ADX counts only the new connections that remain in effect at the end of the
one-second interval. If a connection is opened and terminated within the interval, the ServerIron ADX
does not include the connection in the total for the server.
To limit the number of new TCP connections a cache can receive each second, enter commands
such as the following.
ServerIronADX(config)# server cache-name C1 5.6.7.8
ServerIronADX(config-rs-C1)# max-tcp-conn-rate 2000
Syntax: max-tcp-conn-rate <num>
The <num> variable specifies the maximum number of connections per second. There is no
default.
Syntax: port <TCP/UDP-portnum> max-tcp-conn-rate <num>
The <TCP/UDP-portnum> variable specifies the application port.
The <num> variable specifies the maximum number of connections per second.
You also can specify the connection rate for an individual port.
ServerIronADX(config)# server cache-name C1 5.6.7.8
ServerIronADX(config-rs-C1)# port http
ServerIronADX(config-rs-C1)# port http max-tcp-conn-rate 2000