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Application Delivery (ADX)

Setting/Changing the load-balancing dynamic predictor

by pmorrissey on ‎05-21-2009 02:10 AM - edited on ‎10-30-2013 05:43 PM by bcm1 (465 Views)


How to set/change the load-balancing Dynamic Predictor



Set the dynamic predictor at the Virtual (Vip) level and set the real servers with SNMP query requirements.  Define SNMP polling frequency.


Set the frequency of periodic SNMP queries

server snmp-poll 5


Set the dynamic predictor at the VIP level


To change the load-balancing method used by the ServerIron ADX for Virtual Server “vs1” to use dynamic weighted, use the following

server virtual vs1

predictor dynamic-weighted direct oid 1


To configure a dynamic-weighted reverse predictor, use the following

predictor dynamic-weighted reverse oid 1 max 50


Syntax: predictor dynamic-weighted reverse oid <ID> [max <value>]

Where DECIMAL Max value - reverse weight = direct weight


Set the SNMP setting for the real servers(s)

A SNMP Object ID (OID) should be configured under a real server. An OID represents the weight of the real

server, for example server CPU utilization or its memory usage.


To configure SNMP query requirements use the following

snmp-request 1

Syntax: snmp-request oid <ID> <string>

• <ID>—snmp-request entry identification, decimal value 1 - 256

• <string>—ASCII string ASN.1 format -


SNMP versions 1 and 2 use community strings to restrict SNMP access. The administrator must configure an

SNMP community string to match with those configured in all the real servers.


snmp-request community public



Sample Script/Code/Configuration


server snmp-poll 5


server real rs1

snmp-request community public port 161

snmp-request oid 1

snmp-request oid 2

port http

port http keepalive

port http url "HEAD /"


server virtual vs1

predictor dynamic-weighted direct oid 1

port http

bind http rs1 http rs2 http


Tips / Caveats


Further Reading

Setting/Changing load-balancing distribution predictor (non-dynamic) and weight of servers

Consult Product Documentation for Further info.