Global Catalogs Test

The global catalog is a distributed data repository that contains a searchable, partial representation of every object in every domain in a multidomain active directory domain services (AD DS) forest. The global catalog is stored on domain controllers that have been designated as global catalog servers and is distributed through multimaster replication.

The global catalog enables searching for active directory objects in any domain in the forest without the need for subordinate referrals, and users can find objects of interest quickly without having to know what domain holds the object. The global catalog makes the directory structure within a forest transparent to users who perform a search. For example, if you search for all printers in a forest, a global catalog server processes the query in the global catalog and then returns the results. Without a global catalog server, this query would require a search of every domain in the forest.

This test monitors the global catalogs in the target domain controller and reports the number of catalogs that are currently available and unavailable. This way, the test enables administrators to determine whether/not adequate global catalogs are available in the domain controller to handle the request load.

Target of the test : An Active Directory or Domain Controller on Windows

Agent deploying the test : An internal agent

Outputs of the test : One set of results for every Active Directory site that is being monitored

Configurable parameters for the test
Parameters Description

Test period

This indicates how often should the test be executed.


The IP address of the machine where the Active Directory is installed.


The port number through which the Active Directory communicates. The default port number is 389.

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

Total global catalogs

Indicates the total number of global catalogs on the domain controller being monitored.



Available global catalogs

Indicates the number of global catalogs that are currently available on the domain controller.



Unavailable global catalogs

Indicates the number of global catalogs that are currently unavailable on the domain controller.


If the value of this measure is equal to the value of the Total global gatalogs measure or is higher than that of the Available global catalogs measure, it indicates that enough global catalogs may  not be available on the domain controller to process user logon requests and search requests. As a result, requests may fail.

Percent unavailable global catalogs

Indicates percentage of global catalogs that are currently unavailable.


A high value indicates that too many global catalogs are unavailable for request processing. This in turn can cause many user logon and search requests to the domain controller to fail. Ideally therefore, the value of this measure should be very low.