Brocade Virtual ADX Server Load Balancing Guide (Supporting ADX v03.1.00) User Manual
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Brocade Virtual ADX Server Load Balancing Guide
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Miscellaneous health check settings
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The graph on the right shows how the maximum number of possible HTTP connections for real
server rs1 increases over the slow-start period:
•
Ten seconds after going online, the maximum number of HTTP connections real server rs1 can
have is 300: a maximum of 10 (rate 1) new HTTP connections per second for 30 (interval 1)
seconds equals 300 total HTTP connections for real server rs1.
•
After 30 seconds, the maximum number of HTTP connections for real server rs1 increases by
20 (rate 2) connections per second, until 600 HTTP connections (the ceiling specified by the
max-connections variable in the slow-start list) is reached. This ceiling of concurrent 600 HTTP
connections applies for the entire time the server is active; the Brocade Virtual ADX allows the
server no more than this number of concurrent HTTP connections.
Applying a user-configured slow-start mechanism to multiple ports
To apply a user-configured slow-start mechanism to more than one port, create slow-start lists for
each port and apply them to ports on one or more real servers. For example, to configure a
slow-start mechanism for HTTP (port 80) and SSL (port 443), enter commands such as the
following.
Virtual ADX(config) #server port 80
Virtual ADX(config-port-80)#slow-start 100 10 30 20 30 600
Virtual ADX(config-port-80)#slow-start 101 20 30 40 30 1500
Virtual ADX(config-port-80)#exit
Virtual ADX(config)#server port 443
Virtual ADX(config-port-80)#slow-start 101 20 60 40 120 2400
Virtual ADX(config-port-80)#exit
Virtual ADX(config)#server real-name rs2 192.168.1.2
Virtual ADX(config-rs-rs2)#port http
Virtual ADX(config-rs-rs2)#port http slow-start 100
Virtual ADX(config-rs-rs2)#exit
Virtual ADX(config)#server real-name rs3 192.168.1.3
Virtual ADX(config-rs-rs3)#port http
Virtual ADX(config-rs-rs3)#port http slow-start 101
Virtual ADX(config-rs-rs3)#port ssl
Virtual ADX(config-rs-rs3)#port ssl slow-start 101
Virtual ADX(config-rs-rs3)#exit
The commands create two slow-start lists for port 80 (HTTP) and one for port 443 (SSL). Slow-start
list 100 for port 80 is applied to the HTTP port on real server rs2. Slow-start list 101 for port 80 is
applied to the HTTP port on real server rs3. Slow-start list 101 for port 443 is applied to the SSL
port on real server rs3. Note that slow-start list 101 for port 80 has no relation to slow-start list 101
for port 443.
In this configuration, port 80 on real server rs2 and ports 80 and 443 on real server rs3 are each
subject to a user-configured slow-start mechanism. All other ports on the real servers are subject to
the default slow-start mechanism described in
“Default port slow-start mechanism”
Globally disabling or re-enabling the slow-start mechanism
You can globally disable the mechanism. When you disable the slow-start mechanism, the Brocade
Virtual ADX can immediately send up to the maximum number of connections specified for the real
server when the server becomes available. Disabling slow-start does not remove the slow-start
configuration information from the real servers.
To re-activate slow-start, globally disable the feature.
Virtual ADX(config)#server no-slow-start