Brocade Virtual ADX Server Load Balancing Guide (Supporting ADX v03.1.00) - Manual (Page 67)

Brocade Virtual ADX Server Load Balancing Guide 51
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Primary and backup servers
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remotely-attached servers (configured using the server remote-name command) as their
backup servers.
Optionally, configure the individual applications on the VIPs to continue using the backup
servers following a failover, instead of returning to the primary servers.
Designating a real server as a backup
By default, the virtual server uses the locally attached real servers as the primary load-balancing
servers and uses the remotely attached servers as backups.
To designate a real server to be a backup server, enter the following command.
Virtual ADX(config-rs-R3)#backup
Syntax: [no] backup
In order for the backup functionality to operate, you must also apply the lb-pri-servers command.
Enabling a VIP to use the primary and backup servers
To enable a VIP to use the servers designated as backups only as backups, and use the other
servers as the load-balancing servers, enter the following command at the configuration level for
the VIP.
Virtual ADX(config-vs-VIP1)#port http lb-pri-servers
This command enables VIP1 to use the backup and primary servers for application port HTTP.
The port http lb-pri-servers command is needed for the backup functionality to operate, regardless
of the real servers you have, local or remote. For example, even if all your real servers are local and
you have one designated as backup, it will not be used as a backup unless you apply this
command.
To configure the VIP and application port to continue using the backup servers even after the
primary servers become available again, use the backup-stay-active parameter, as in the following
example.
Virtual ADX(config-vs-VIP1)#port http lb-pri-servers backup-stay-active
Syntax: [no] port tcp/udp-port lb-pri-servers [backup-stay-active]
When configuring the backup-stay-active option you might expect that all traffic will go to the
backup server even when the primary comes back up however this may not be the case in some
situations as described in the following.
The client traffic is handled by either primary servers only or by the backup servers only at all times.
You can use the show server backup-associated state to see which server is currently active as
shown in the following example.
Syntax: show server backup-associated-state [vip-name [application-port]]
Virtual ADX(config-vs-VIP1)# show server backup-associated state
Backup state info: *indicates the current selection
Virtual server: vip1 Status: enabled IP: 10.1.1.100
http:
Primary: rs1: http(Active)* Backup: rs2: http(Active)