Equalizer Server Status Test

The real test of the efficiency of a load balancer lies in its ability to uniformly distribute load across the servers in a cluster, thereby ensuring the peak performance and continuous availability of the dependent services. Using the Equalizer Server Status test, administrators can accurately judge the efficiency and effectiveness of the equalizer. This test monitors the connection and calculated load on each server in a cluster,  promptly detects load imbalances, and alerts administrators to them, so that they can quickly resolve the issue.

Target of the test : A Coyote Point Equalizer

Agent deploying the test : An external agent

Outputs of the test : One set of results for each server in each cluster managed by the equalizer

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 this test is to be configured.

SNMPPort

The port at which the monitored target exposes its SNMP MIB; the default is 161.

SNMPVersion

By default, the eG agent supports SNMP version 1. Accordingly, the default selection in the SNMPversion list is v1. However, if a different SNMP framework is in use in your environment, say SNMP v2 or v3, then select the corresponding option from this list.

SNMPCommunity

The SNMP community name that the test uses to communicate with the firewall. This parameter is specific to SNMP v1 and v2 only. Therefore, if the SNMPVersion chosen is v3, then this parameter will not appear.

Username

This parameter appears only when v3 is selected as the SNMPversion. SNMP version 3 (SNMPv3) is an extensible SNMP Framework which supplements the SNMPv2 Framework, by additionally supporting message security, access control, and remote SNMP configuration capabilities. To extract performance statistics from the MIB using the highly secure SNMP v3 protocol, the eG agent has to be configured with the required access privileges – in other words, the eG agent should connect to the MIB using the credentials of a user with access permissions to be MIB. Therefore, specify the name of such a user against this parameter. 

Context

This parameter appears only when v3 is selected as the SNMPVERSION. An SNMP context is a collection of management information accessible by an SNMP entity. An item of management information may exist in more than one context and an SNMP entity potentially has access to many contexts. A context is identified by the SNMPEngineID value of the entity hosting the management information (also called a contextEngineID) and a context name that identifies the specific context (also called a contextName). If the Username provided is associated with a context name, then the eG agent will be able to poll the MIB and collect metrics only if it is configured with the context name as well. In such cases therefore, specify the context name of the Username in the Context text box.  By default, this parameter is set to none.

AuthPass

Specify the password that corresponds to the above-mentioned Username. This parameter once again appears only if the SNMPversion selected is v3.

Confirm Password

Confirm the AuthPass by retyping it here.

AuthType

This parameter too appears only if v3 is selected as the SNMPversion. From the Authtype list box, choose the authentication algorithm using which SNMP v3 converts the specified username and password into a 32-bit format to ensure security of SNMP transactions. You can choose between the following options:

  • MD5 – Message Digest Algorithm
  • SHA – Secure Hash Algorithm

EncryptFlag

This flag appears only when v3 is selected as the SNMPversion. By default, the eG agent does not encrypt SNMP requests. Accordingly, the this flag is set to No by default. To ensure that SNMP requests sent by the eG agent are encrypted, select the Yes option. 

EncryptType

If this EncryptFlag is set to Yes, then you will have to mention the encryption type by selecting an option from the EncryptType list. SNMP v3 supports the following encryption types:

  • DES – Data Encryption Standard
  • AES – Advanced Encryption Standard

EncryptPassword

Specify the encryption password here.

Confirm Password

Confirm the encryption 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.

Data Over TCP

By default, in an IT environment, all data transmission occurs over UDP. Some environments however, may be specifically configured to offload a fraction of the data traffic – for instance, certain types of data traffic or traffic pertaining to specific components – to other protocols like TCP, so as to prevent UDP overloads. In such environments, you can instruct the eG agent to conduct the SNMP data traffic related to the monitored target over TCP (and not UDP). For this, set this flag to Yes. By default, this flag is set to No.

Measurements made by the test
Measurement Description Measurement Unit Interpretation

Server load

Indicates the current calculated load value for this server.

Number

This indicates the workload on the server. By comparing the value of this measure across all the servers in a cluster, you can instantly identify irregularities in load balancing. If found necessary, you can reconfigure the load balancing rules to ensure uniform load distribution across servers.

Response time

Indicates how quickly this server is currently responding to client requests.

ms

It is the job of a load balancer to ensure minimal response time for client requests. A high value for this measure could therefore indicate a defective load balancer or one that is improperly configured. Further investigation is hence necessary in this case to identify the root-cause of the anomaly.   

Current connections

Indicates the number of connections that were active on this server during the last measurement period.

Number

The indicates the connection load on the server. By observing the graph of this measure over time, you can analyze the rate of growth of the load on the server. By comparing the value of this measure across all the servers in a cluster, you can instantly identify overloaded servers; this in turn brings irregularities in load balancing to light.

Total connections

Indicates the number of current connections to this server.

Number

If a sudden/consistent increase in the value of this measure is noticed, you might have to investigate further to identify the reason for this occurrence.

Idle time

Indicates the time for which this server was idle.

Secs

Ideally, the value of this measure should be low. A high value indicates that the server has remained unused for a long time. This could be owing to inconsistencies in load balancing or because the server is unavailable for use.