Real Service Test

Physical servers a.k.a Real Services (also referred as real server) are those that are bound to a virtual server in a server farm of the vAPV Application Delivery Controller. Whenever a request is received from a user, the virtual server bound to the real server responds to those requests by channelizing the requests to the real servers that are currently available. Since multiple virtual hosts can be pointed to the same set of real servers, having a good number of supported VIPs presents more flexibility in the architecture and design of the site or application. There may be upto 100 real servers connected to a single virtual host and the same set of real servers can be pointed to multiple virtual hosts to provide more flexibility in the architecture and design of the delivery controller. The delivery controller installed in large environments often receives thousands of client requests per second, which should be responded without any time delay. In such cases, the virtual host sends the requests continuously to the available real servers bound to it. If the real server is experiencing any technical glitch or a slowdown or if the real server is currently overloaded, the delivery controller may not be effective in responding to the client requests thus causing inconsistencies in the load balancing functionality. To avoid such inconsistencies, it is necessary to monitor the health and the request processing details of the real servers. This is where the Real Service test exactly helps!

For each real server configured on the delivery controller, this test continuously monitors the current state of the real servers and also reveals how well each server transmits and receives data. In addition, this test detects inconsistencies in load-balancing early on and warns administrators of possible deviations proactively.

Target of the test : An Array Application Delivery Controller

Agent deploying the test : A remote agent

Outputs of the test : One set of results for each real server on the Array Application Delivery Controller that is to be monitored.

Configurable parameters for the test
Parameter Description

Test Period

How often should the test be executed.

Host

The IP address of the host that is being monitored.

SSH Username and
SSH Password

Specify the credentials of a user who has the right to execute CLI (command-line interface) commands on the target delivery controller and pull out metrics via SSH.

Confirm Password

Confirm the SSH Password by retyping it here.

SSH Port

Specify the SSH port of the target delivery controller here; The default value is 22.

SSH Enable Password

The delivery controller offers three levels or modes to the ArrayOS. The modes are given below:

  • User Mode - In this mode, user can perform the authorized and basic operations and non-critical functions.
  • Enable Mode - When this mode is selected, the user can run majority of commands for view data.
  • Config Mode - Using this level, the user can change the configuration of the delivery controller for global configuration and access (Using CLI commands).

The SSH Enable password is the password that is needed for the user to access the commands when the Enable Mode is selected.

Confirm Password

Confirm the SSH Enable Password by retyping it here.

Timeout

Specify the duration (in seconds) within which the SNMP query executed by this test should time out in this text box. The default is 10 seconds.

Measurements made by the test
Measurement Description Measurement Unit Interpretation

Status

Indicates the current status of this real server.

 

The values of this measure and their corresponding numeric values are listed below:

Measure Value Numeric Value
Up 1
Down 2

Note:

By default, this measure reports one of the Measure Values listed in the table above to indicate the current status of this real server. In the graph of this measure however, the real server status will be represented using the numeric equivalents.

Data transmitted

Indicates the amount of data that was transmitted from this real server during the last measurement period.

KB

Compare the values of these measures across nodes to identify the server that is handling maximum traffic.

Data received

Indicates the amount of data that was received by this real server during the last measurement period.

KB

Packets transmitted

Indicates the number of packets that were transmitted from this real server during the last measurement period.

Number

Compare the value of these measures across the real servers to identify the real server that is experiencing the maximum traffic.

Packets received

Indicates the number of packets that were received by this real server during the last measurement period.

Number

Maximum connection count

Indicates the maximum number of connections that are established on this real server.

Number

This measure is a good indicator of the load on the real server.

Current connection count

Indicates the number of connections that are currently active on this real server.

Number

 

Outstanding request count

Indicates the number of requests that are currently in an outstanding state on this real server.

Number

 

Hits

Indicates the number of requests received by this real server.

Number

A value close to 100% indicates that the real server is currently overloaded.

Average bandwidth transmitted

Indicates the rate at which data is transmitted from this real server.

Bits/second

 

Average bandwidth received

Indicates the rate at which data is received by this real server.

Bits/second

 

Average response time

Indicates the average time taken by this real server to respond to the requests.

Millisecond