eG Monitoring
 

Measures reported by CtxNsGslbDomainTest

GSLB (Global Server Load Balancing) is a Domain Name Server (DNS)-based solution that load balances services between geographically distributed locations. GSLB relies on DNS for directing client requests. GSLB enables the NetScaler appliance to make intelligent network traffic direction decisions based on the configured method. GSLB responds to DNS requests for a domain name with an IP address of a member service. Which service IP is returned is dependent on the load-balancing algorithm used - for example least connection, simple round robin or more commonly used, proximity to the client (or the clients local DNS to be precise).

To understand how efficiently a Netscaler applicance configured with GSLB performs load-balancing, you first need to understand the DNS request load on the appliance and the most-requested domain names. The NS GSLB Domains test provides this information.

This test tracks the DNS requests received by the Netscaler appliance, automatically discovers the domain names that are requested, and reports the number of requests received for each domain name. Besides enabling you to instantly capture a sudden or a steady increase in load, this test also helps you point to those domains that are requested the maximum. This test can also provide early pointers to what could be a potential request processing bottleneck on the Netscaler appliance.

The measures made by this test are as follows:

Measurement Description Measurement Unit Interpretation
Dns_queries_received Indicates the number of DNS requests received for this domain name during the last measurement period. Number A high value for this measure could indicate an increase in the load on the Netscaler appliance. Under such circumstances, you can quickly compare the value of this measure across domains to identify the domain that has received the maximum requests. You may want to observe the traffic to this domain for a while to know whether there was a consistent increase in the load or was it just a sudden occurrence. A consistent rise in the number of requests could indicate a potential processing bottleneck.