Technical data

ServerIron ADX Advanced Server Load Balancing Guide 45

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Other transparent cache switching options

Selecting server selection methods with cache groups

By default, the SSL and HTTP protocols use a hash method based on the source and destination IP

addresses to select a cache server within a cache group. All other protocols use the least

connection method by default.

To change the method of selecting a server within a cache group, enter a command such as the

following:

ServerIronADX(config)# server cache-group 1

ServerIronADX(config-tc-1)# predictor least-connection port http

ServerIronADX(config-tc-1)# predictor hash port ftp

Syntax: predictor { hash | least-connection } port <portname or number>

The default predictor for SSL and HTTP is the hash method described in “Increasing the TCS hash

bucket count” on page 54.

The default predictor for all other protocols is least-connection.

NOTE

If multiple services use the hash method to select a cache server, Brocade recommends that you

group those services together using the hc-track-group command to maintain persistence of traffic

across those services. For example, both http and https use hashing by default. To ensure that traffic

persists to the same cache servers, you should group these services together. For more information

on track port group health checks, see “Application port grouping” in the ServerIron ADX Server

Load Balancing Guide.

Examples

In the following example, SSL traffic uses the hash mechanism to select a cache server which is

the default action. SSL and HTTP traffic can use one hash table, This means that traffic having the

same hash value will go to the same cache server whether it is SSL traffic or HTTP traffic.

NOTE

This example shows commands that are valid on the ServerIron ADX device only when it is running

the Layer 3 router image.

ServerIronADX(config)# server cache-name cs1 192.168.0.1

ServerIronADX(config-rs-cs1)# port http

ServerIronADX(config-rs-cs1)# port http url "HEAD/"

ServerIronADX(config-rs-cs1)# port ssl

ServerIronADX(config-rs-cs1)# hc-track-group 80 443

ServerIronADX(config-rs-cs1)# exit

2001:db8:0102:0303:7::1 Any C2

2001:db8:0102:0304:8::1 Any C3

ffff:ffff:ffff:ffff:: ::ffff 2001:db8:0102:0303:6::1 2001:db8:0102:1 C1

2001:db8:0102:0303:7::1 2001:db8:0304:1 C1

2001:db8:0102:0304:8::1 2001:db8:0506:2 C2

TABLE 4 Example TCS hash masks (IPv4+IPv6) (Continued)

Destination mask Source mask Destination IP address Source IP address Cache server