Brocade Virtual ADX Server Load Balancing Guide (Supporting ADX v03.1.00) - Manual (Page 53)

Brocade Virtual ADX Server Load Balancing Guide 37
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Sticky and concurrent connections
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Configuring stickiness based on client’s subnet
The sticky function causes the Brocade Virtual ADX to send all of a client’s requests for a given
application to the same real server during the client’s session with the server. By default, the
stickiness is based on the client's IP address. You can configure the Brocade Virtual ADX to base
the stickiness on the client’s subnet, rather than IP address. All requests originating from a specific
subnet for a given application are sent to the same real server.
For example, to send all HTTP requests originating from a given subnet to the same real server,
enter commands such as the following.
Virtual ADX(config)#server virtual-name-or-ip vs1 10.10.10.10
Virtual ADX(config-vs-vs1)#port http
Virtual ADX(config-vs-vs1)#port http client-subnet-sticky prefix-length 24
Syntax: [no] port portnum client-subnet-sticky prefix-length prefix-length
or
Syntax: [no] port portnum client-subnet-sticky subnet-mask client-subnet-mask
In this example, client requests from subnet 192.168.9.x would go to the same real server. Sub-net
sticky connections are aged out according to the sticky age setting, in the same way regular sticky
connections are aged out.
The features port sticky and port client-subnet-sticky cannot be configured together on the same
port on the same virtual server.
Setting the sticky age
You can age out inactive sticky server connections. A connection is sticky if you configure the
Brocade Virtual ADX to send successive requests from the same client for the same application
port to the same real server, instead of load balancing the requests to different real servers.
Sticky connections are defined on a virtual server port of an SLB switch when a service request by
a client mandates a series of sequential TCP or UDP port connections to be served by the same
real server. For example, if a client is accessing dynamically generated pages, the client must
consistently attach to the same server, otherwise the state information will be lost.
The sticky age is a global setting applying to all virtual servers; you can also set the sticky age for an
individual virtual server. The sticky age for the individual virtual server overrides the global setting.
To set the sticky age globally, enter a command such as the following.
Virtual ADX(config)#server sticky-age 20
To set the sticky age for an individual virtual server, enter commands such as the following.
Virtual ADX(config)#server virtual-name-or-ip v1
Virtual ADX(config-vs-v1)#sticky-age 20
Syntax: [no] server sticky-age minutes
The minutes variable is the sticky age in minutes. Enter an integer from 2 to 60. The default is 5
minutes.