eG Monitoring
 

Measures reported by CtxNsGslbSrvTest

A GSLB service is usually a representation of a load balancing or content switching virtual server, although it can represent any type of virtual server. The GSLB service identifies the virtual server's IP address, port number, and service type. GSLB services are bound to GSLB virtual servers on the NetScaler appliances managing the GSLB sites.

A GSLB service bound to a GSLB virtual server in the same data center is local to the GSLB virtual server. A GSLB service bound to a GSLB virtual server in a different data center is remote from that GSLB virtual server. A GSLB virtual server has one or more GSLB services bound to it, and load balances traffic among those services. It evaluates the configured GSLB methods (algorithms) to select the appropriate service to which to send a client request. Because the GSLB services can represent either local or remote servers, selecting the optimal GSLB service for a request has the effect of selecting the data center that should serve the client request.

Using this test, you can monitor the request, response, and data load on the individual services configured on the Netscaler appliance, evaluate the efficiency with which the appliance distributes this load to the services, and promptly detect irregularities (if any) in load-balancing.

The measures made by this test are as follows:

Measurement Description Measurement Unit Interpretation
Server_state Indicates the current state of the virtual server with which this service is bound.   If the virtual server is up, then the value of this measure is Up. If the virtual server is down, then the value of this measure is Down.

The numeric values that correspond to these measure values have been listed in the table below:

Measure Value Numeric Value
Up 0
Down 1
Out of service 2
Transition out of service 3
Down when going out of service 4
Unknown -1

Note:

By default, this measure reports the above-mentioned Measure Values while indicating whether a virtual server is up/down. However, in the graph of this measure, the Measure Values will be represented using their corresponding numeric equivalents only.

The detailed diagnosis of this measure reports the service type, the primary IP address of the service, and its primary port.
Vserver_health Indicates the load on the service that is calculated from the bound load based monitor. Percent In a load-balanced setup, the value of this measure should be low or should be more or less the same for all services. A very high value for this measure could indicate that the service is overloaded. You may then want to consider fine-tuning your GSLB policies and metric exchange policies to ensure that the load-balancing irregularities are removed.
Client_cons Indicates the number of current client connections to this service Number These are good measures of the connection load on a service. By comparing the value of each of these measures across services, you can instantly identify overloaded services and promptly detect irregularities in load-balancing.
Server_cons Indicates the number of connections to the actual servers behind the virtual server that is bound to this service. Number
Client_cons_est Indicates the number of client connections to this service that are currently in an ESTABLISHED state. Number
Server_cons_est Indicates the number of connections to the actual server behind the virtual server that is bound to this service that are currently in an ESTABLISHED state. Number
Req_data_received Indicates the amount of request data received by the virtual server bound to this GSLB service during the last measurement period. MB These are good measures of the request and response load on a service. By comparing the value of each of these measures across services, you can instantly identify overloaded services and promptly detect irregularities in load-balancing.

In the event that such irregularities come to light, you may want to consider fine-tuning the GSLB policies and/or GSLB methods and/or metric exchange policies supported by the system to ensure that the appliance takes intelligent load-balancing decisions.
Res_data_received Indicates the amount of response data received by the virtual server bound to this GSLB service during the last measurement period. MB
Req_received Indicates the number of requests received by the virtual server bound to this GSLB service during the last measurement period. Number
Res_received Indicates the number of responses by the virtual server bound to this GSLB service during the last measurement period. Number
Vserver_hits Indicates the number of times this service has been provided during the last measurement period. Number If the value of this measure is equal to the number of requests received for this service, then it indicates that all requests have been fulfilled. On the contrary, if the value of this measure is less than the number of requests received, it could indicate that one/more requests could not be serviced. This is a cause for concern.
Spill_threshold Indicates the spillover threshold that was set for this GSLB service during the last measurement period. Number  
No_of_times_spillover Indicates the number of times the spill over threshold was exceeded by this GSLB service during the last measurement period. Number A low value is preferred for this measure. A high value will be reported due to inefficient load-balancing by the GSLB service.