eG Monitoring
 

Measures reported by ADGCAvailTest

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.

The measures made by this test are as follows:

Measurement Description Measurement Unit Interpretation
Total_gc Indicates the total number of global catalogs on the domain controller being monitored. Number  
Avail_gc Indicates the number of global catalogs that are currently available on the domain controller. Number  
Unavail_gc Indicates the number of global catalogs that are currently unavailable on the domain controller. Number If the value of this measure is equal to the value of the Total global catalogs 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_gc Indicates percentage of global catalogs that are currently unavailable. Percent 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.