Load Balancing Service Groups Test

A service group is a representation of one/more services. For each service in a service group, this test reports the state of the virtual server bound to the service, tracks the packet/data traffic flowing into and out of each service, and thus reveals how uniformly load is distributed across all the services in a group.

Target of the test : A NetScaler VPX/MPX

Agent deploying the test : A remote agent

Outputs of the test : One set of results for each service in each service group configured on the NetScaler appliance being monitored.

Configurable parameters for the test
Parameter Description

Test Period

How often should the test be executed.

Host

The IP address of the host for which the test is being configured.

NetScaler Username and NetScaler Password

To monitor a NetScaler device, the eG agent should be configured with the credentials of a user with read-only privileges to the target NetScaler device. Specify the credentials of such a user in the NetScaler Username and NetScaler Password text boxes.

Confirm Password

Confirm the NetScaler Password by retyping it here.

SSL

The eG agent collects performance metrics by invoking NITRO (NetScaler Interface Through Restful interfaces and Objects) APIs on the target NetScaler device. Typically, the NITRO APIs can be invoked through the HTTP or the HTTPS mode. By default, the eG agent invokes the NITRO APIs using the HTTPS mode. This is why, the SSL flag is set to Yes by default. If the target NetScaler device is not SSL-enabled, then the NITRO APIs can be accessed through the HTTP mode only. In this case, set the SSL flag to No.

Show Up Server Only

The default setting of this flag is No; this indicates that this test, by default, monitors all the services configured in a NetScaler device. If you want the test to monitor only those services that are up and running currently, then set this value to Yes.

Detailed Diagnosis

To make diagnosis more efficient and accurate, the eG Enterprise embeds an optional detailed diagnostic capability. With this capability, the eG agents can be configured to run detailed, more elaborate tests as and when specific problems are detected. To enable the detailed diagnosis capability of this test for a particular server, choose the On option. To disable the capability, click on the Off option.

The option to selectively enable/disable the detailed diagnosis capability will be available only if the following conditions are fulfilled:

  • The eG manager license should allow the detailed diagnosis capability
  • Both the normal and abnormal frequencies configured for the detailed diagnosis measures should not be 0.
Measurements made by the test
Measurement Description Measurement Unit Interpretation

Server state

Indicates the current state of the virtual server bound to this service in the NetScaler device.

 

The values that this measure can report and their numeric equivalents are 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

Note:

By default, this measure reports the above-mentioned Measure Values to indicate the state of the virtual server. However, in the graph of this measure the virtual server state will be represented using the corresponding numeric equivalents only.

The detailed diagnosis of this measure shows the Service Type, Primary Port, the Primary IP address, Weight (The higher the weight, the higher the percentage of requests sent to each service), Server ID and Hash ID of the virtual server.

Effective state

Indicates the effective state of virtual server that are bound to this service.

 

Effective state of a service is the state derived from the Load Balancing virtual server bound to that service in each group.

The values that this measure can report and their numeric equivalents are listed in the table below:

Measure Value Numeric Value
Up 100
Partial-Up 75
Out of Service

50

Partial-Down

25

Down

10

Note:

By default, this measure reports the above-mentioned Measure Values to indicate the effective state of the virtual server. However, in the graph of this measure the effective state will be represented using the corresponding numeric equivalents only.

Is server enabled state?

Indicates whether the virtual server bound to this service is enabled or not.

 

The state of a service is the state derived from the monitors bound to that service in each service group.

The values that this measure can report and their numeric equivalents are listed in the table below:

Measure Value Numeric Value
Yes 1
No 0

Note:

By default, this measure reports the above-mentioned Measure Values to indicate the state of the virtual server bound to each service in each service group. However, in the graph of this measure the service group state will be represented using the corresponding numeric equivalents only - i.e., 0 or 1.

Available servers

Indicates the number of virtual servers that are bound to this service.

Number

This measure will report a value only for the Summary descriptor.

Servers in UP state

Indicates the number of virtual servers that are in the UP state.

Number

This measure will report a value only for the Summary descriptor.

Percentage of UP state servers

Indicates the percentage of virtual servers that are in the UP state.

Percent

This measure will report a value only for the Summary descriptor.

Server connections

Indicates the number of current connections to the actual servers behind the virtual server bound to this service.

Number

These measures serve as good indicators of the current workload of a service.

 

Client connections

Indicates the number of current client connections to this service.

Number

Requests in idle queue/reuse pool

Indicates the number of requests in the idle queue or the reuse pool.

Number

Ideally, the value of this measure should be low. A very high value indicates that too many idle connections have been placed in the idle queue/reuse pool and have not been reused yet. Such requests drain resources unnecessarily. To avoid this, you can limit the number of connections that can be added to the connection reuse pool of the appliance. You can add an HTTP profile and attach it at a virtual server (VServer) or a service level. You can use this profile to limit the number of connections that can be added to the connection reuse pool.

Avg TTFB between NetScaler and server

Indicates the average response Time to First Byte (TTFB) to the NetScaler device from the server.

Seconds

Time to First Byte is a metric used to measure response time, calculated based on the time it takes to send a GET Request and receive a GET Response back from a server. A high value is a clear indication of network congestion or connection failure.

Maximum open connections allowed

Indicates the maximum number of open connections that are allowed on this service.

Number

 

Surge queue

Indicates the number of requests in the surge queue of this service.

Number

The NetScaler device can be used to limit the number of simultaneous requests that are passed on to a server. When a request is completed, additional requests are forwarded to the server. If a request arrives and the server is handling the maximum configured number of requests, the NetScaler device places the new request in a surge queue, where the request waits for its turn to be sent to the server for processing. The surge queue allows a server to run at peak capacity without the risk of having it spiral out of control because of a surge of incoming requests.

Server connections in established state

Indicates the number of connections to the virtual server bound to this service that are currently in ESTABLISHED state.

Number

 

Request data received

Indicates the amount of request data received on this service group or virtual server during the last measurement period.

MB

 

Response data received

Indicates the amount of response data received on this service group or virtual server during the last measurement period.

Number

 

Request packets

Indicates the number of packets received on this service group or virtual server during the last measurement period.

Number

 

Response packets

Indicates the number of packets sent from this service group or virtual server during the last measurement period.

Number