Brocade Virtual ADX Server Load Balancing Guide (Supporting ADX v03.1.00) - Manual (Page 241)

Brocade Virtual ADX Server Load Balancing Guide 225
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Miscellaneous health check settings
4
Minimum healthy real servers under VIP port
The minimum healthy servers feature allows a VIP port to handle traffic only if the a configured
number of real server ports bound to the VIP port are healthy and UP. This would allow virtual
servers to stay down unless they have enough server capacity to handle the load.
Command line interface
The command to turn on minimum healthy servers feature is under virtual server configuration.
Virtual ADX(config)#server virtual-name-or-ip v1 10.1.1.1
Virtual ADX(config-virtual-server-v1) port 80
Virtual ADX(config-virtual-server-v1) port 80 minimum-servers 2
Virtual ADX(config-virtual-server-v1) bind http rs1 http rs2 http rs3 http rs4
http
The VIP will not answer connections on port http until at least 2 of the real or remote servers bound
to port http are UP.
Server port bring-up enhancement
The Brocade Virtual ADX currently brings a port up after it passes the configured health-check. This
feature allows user to configure retries for bringup, so that the Brocade Virtual ADX brings up a port
only after the configured number of retries have passed. The real server port will need to pass the
configured number of checks before coming up.
Command line interface
The command to turn on server port bring-up enhancement feature is under port profile
configuration.
Virtual ADX(config)#server port 80
Virtual ADX(config-port-80) bringup-retries 10
The Brocade Virtual ADX will now bring port 80 up only after it has passed the number variable of
health-checks. Previously port 80 would have been marked as up after the first time it passes a
health-check.
Slow-start mechanism
When the Brocade Virtual ADX begins sending client requests to a real server that has recently
gone online, it allows the server to ramp up by using the slow-start mechanism. The slow-start
mechanism allows a server (or a port on the server) to handle a limited number of connections at
first and then gradually handle an increasing number of connections until the maximum is
reached.
The Brocade Virtual ADX uses two kinds of slow-start mechanisms:
• The non-configurable server slow-start mechanism applies to a real server that has just gone
online
• The configurable port slow-start mechanism applies to individual TCP application ports that
have just been activated on a real server