When the NetScaler performs load balancing, it creates and maintains a number of sessions between the client and servers. In scenarios such as DSR setup or intrusion detection system (IDS) load balancing, the NetScaler can perform load balancing without creating sessions. To prevent creation of sessions, you must configure a sessionless virtual server in the NetScaler. The sessionless virtual server does not allocate any resources on the NetScaler, thereby saving the memory that the specific deployment consumes.
When you enable the sessionless option, the NetScaler performs load balancing on a per-packet basis. When a sessionless virtual server is configured, the sessionless virtual server forwards the packets to a server selected using load balancing methods. While forwarding the packet, the NetScaler changes the destination MAC address to the server MAC address.
For sessionless load balancing
- Enable MBF mode
- Enable MAC-Based mode on the sessionless load balancing virtual server
- Enable USIP mode on services (because the IP address of the source is not changed)
To set a sessionless virtual server by using the NetScaler command line
set lb vserver <vServerName> -m <RedirectionMode> -sessionless <Value>
To set a sessionless virtual server by using the GUI configuration utility
- In the navigation pane, expand Load Balancing, and then click Virtual Servers.
- In the Load Balancing Virtual Servers page, select the virtual server for which you want to configure sessionless load balancing (for example, Vserver-LB-1), and then click Open.
- On the Advanced tab, under Redirection Mode, click MAC Based.
- Select the Sessionless check box, and click OK.