ADAM Access Details Test

This test measures the load on the AD server in terms of the level of read-write activity on the server and the count of search operations performed by the server. In the process, the test reveals the following:

  • Which AD services initiated the read-write operations? Which of these services generated the maximum I/O load on the server - is it the LSA? the NSPI? the NTDS? SAM? or the replication service? - this information is useful when administrators are faced with an AD overload, as it accurately points them to the probable sources of the load;
  • Which AD service performed the maximum searches on the server? - in the event of an overload, this metric will help you identify that service which could be contributing to the overload;
  • Is the server sized with adequate threads to handle the I/O load?

Note:

This test applies only to Active Directory Servers installed on Windows 2008.

Target of the test : An Active Directory server

Agent deploying the test : An internal agent

Outputs of the test : One set of results for every Active Directory server being monitored.

Configurable parameters for the test
Parameters Description

Test period

This indicates how often should the test be executed.

Host

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

Port

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

Measurements made by the test
Measurement Description Measurement Unit Interpretation

Schema cache hit ratio

Indicates the percentage of object name lookups serviced by the Schema Cache.

Percent

All changes made to Active Directory are validated first against the schema. For performance reasons, this validation takes place against a version of the schema that is held in memory on the domain controllers. This "in-memory version," called the schema cache, is updated automatically after the on-disk version has been updated. The schema cache provides mapping between attribute identifiers such as a database column identifier or a MAPI identifier and the in-memory structures that describe those attributes. The schema cache also provides lookups for class identifiers to get in-memory structures describing those classes.

A low value of this measure indicates that the Directory Service needs high disk read/write activity to perform its job. This results in poor response time of the components available in the Active Directory.

Notify queue size

Indicates the number of pending update notification requests that have been queued and not transmitted.

Number

When any change in the Active Directory occurs, the originating domain controller sends an update notification requests to the other domain controllers.

A high value of this measure indicates that the Active Directory is changing frequently but the update notification requests have not been transmitted to the other domain controllers. This results in a loss of data integrity in the directory store. This problem can be corrected by forcing the replication.

Current threads in use

Indicates the current number of threads in use by the directory service (which is different from the number of threads in the directory service process).

Number

This is the number of threads currently servicing client API calls; it can be used to indicate whether additional processors should be used.

A fluctuating value for this measure indicates a change in the load.

A low value could point to network problems that are preventing client requests from succeeding.

Server binds

Indicates the number of domain controller–to–domain controller binds per second that are serviced by this domain controller.

Binds/Sec

 

Directory reads

Indicates the rate of directory reads.

Reads/Sec

These measures serve as effective indicators of the ability of the AD server to process read, write, and search requests.

Directory writes

Indicates the rate of directory writes.

Writes/Sec

Directory searches

Indicates the number of directory searches per second.

Searches/Sec

DS reads from DRA

Indicates the  percentage of reads on the directory by replication.

Percent

If the AD server is experiencing abnormally high read activity, then, you can compare the value of this measure with the values reported by the DS reads from KCC, DS reads from LSA, DS reads from NSPI, DS reads from NTDS, and DS reads from SAM measures to know which AD service is performing the maximum reads on the AD server - is it the replication service? the LSA? the KCC? the NSPI? the NTDS? or the SAM?

DS reads from KCC

Indicates the percentage of reads performed by the Knowledge Consistency Checker on the directory.

 

Percent

The Knowledge Consistency Checker (KCC) generates the replication topology by specifying what domain controllers will replicate to which other domain controllers in the site. The KCC maintains a list of connections, called a replication topology, to other domain controllers in the site. The KCC ensures that changes to any object are replicated to all site domain controllers and updates go through no more than three connections.

If the AD server is experiencing abnormally high read activity, then, you can compare the value of this measure with the values reported by the DS reads from DRA, DS reads from LSA, DS reads from NSPI, DS reads from NTDS, and DS reads from SAM measures to know which AD service is performing the maximum reads on the AD server - is it the replication service? the LSA? the KCC? the NSPI? the NTDS? or the SAM?

DS reads from LSA

Indicates the percentage of reads performed by the Local Security Authority on the directory.

 

Percent

The Local Security Authority (LSA) is the security subsystem responsible for all interactive user authentication and authorization services on a local computer. The LSA is also used to process authentication requests made through the Kerberos V5 protocol or NTLM protocol in Active Directory.

If the AD server is experiencing abnormally high read activity, then, you can compare the value of this measure with the values reported by the DS reads from DRA, DS reads from KCC, DS reads from NSPI, DS reads from NTDS, and DS reads from SAM measures to know which AD service is performing the maximum reads on the AD server - is it the replication service? the LSA? the KCC? the NSPI? the NTDS?

DS reads from NSPI

Indicates the percentage of reads performed by the Name Service Provider Interface (NSPI) on the directory.

Percent

The Name Service Provider Interface (NSPI)  is the protocol by which Messaging API (MAPI) clients access the AD DS.

Exchange Address Book clients use the client MAPI provider Emsabp32.dll to look up e-mail addresses in the global catalog. The client-side MAPI provider communicates with the server through the proprietary Name Service Provider Interface (NSPI) RPC interface.

If the AD server is experiencing abnormally high read activity, then, you can compare the value of this measure with the values reported by the DS reads from KCC, DS reads from LSA, DS reads from DRA, DS reads from NTDS, and DS reads from SAM measures to know which AD service is performing the maximum reads on the AD server - is it the replication service? the LSA? the KCC? or the NSPI?

DS reads from NTDS

Indicates the percentage of reads performed by the name service directory APIs on the directory.

Percent

If the AD server is experiencing abnormally high read activity, then, you can compare the value of this measure with the values reported by the DS reads from KCC, DS reads from LSA, and DS reads from DRA, DS reads from NSPI, and DS reads from SAM measures to know which AD service is performing the maximum reads on the AD server - is it the replication service? the LSA? the KCC? the NSPI? or the SAM?

DS reads from SAM

Indicates the percentage of reads performed by the Security Account Manager (SAM) on the directory.

Percent

The Security Accounts Manager (SAM) is used for verifying passwords and for checking passwords against any existing password policies that are in effect on a domain controller. 

If the AD server is experiencing abnormally high read activity, then, you can compare the value of this measure with the values reported by the DS reads from KCC, DS reads from LSA, and DS reads from DRA, DS reads from NSPI, and DS reads from NTDS measures to know which AD service is performing the maximum reads on the AD server - is it the replication service? the LSA? the KCC? the NSPI? or the NTDS?

DS writes from DRA

Indicates the  percentage of writes on the AD server by replication.

Percent

If the AD server is experiencing abnormally high write activity, then, you can compare the value of this measure with the values reported by the DS writes from KCC, DS writes from LSA, DS writes from NSPI, DS writes from NTDS, and DS writes from SAM measures to know which AD service is performing the maximum writes on the AD server - is it the replication service? the LSA? the KCC? the NSPI? the NTDS? or the SAM?

DS writes from KCC

Indicates the percentage of writes performed by the Knowledge Consistency Checker on the directory.

 

Percent

If the AD server is experiencing abnormally high write activity, then, you can compare the value of this measure with the values reported by the DS writes from DRA, DS writes from LSA, DS writes from NSPI, DS writes from NTDS, and DS writes from SAM measures to know which AD service is performing the maximum writes on the AD server - is it the replication service? the KCC? the LSA? the NSPI? the NTDS? or the SAM?

DS writes from LSA

Indicates the percentage of writes performed by the Local Security Authority on the directory.

 

Percent

If the AD server is experiencing abnormally high write activity, then, you can compare the value of this measure with the values reported by the DS writes from DRA, DS writes from KCC, DS writes from NSPI, DS writes from NTDS, and DS writes from SAM measures to know which AD service is performing the maximum writes on the AD server - is it the replication service? the LSA? the KCC? the NSPI? the NTDS? or the SAM?

DS writes from NSPI

Indicates the percentage of writes performed by the Name Service Provider Interface (NSPI) on the directory.

Percent

If the AD server is experiencing abnormally high write activity, then, you can compare the value of this measure with the values reported by the DS writes from DRA, DS writes from KCC, DS writes from LSA, DS writes from NTDS, and DS writes from SAM measures to know which AD service is performing the maximum writes on the AD server - is it the replication service? the LSA? the KCC? the NSPI? the NTDS? or the SAM?

DS writes from NTDS

Indicates the percentage of writes performed by the name service directory APIs on the directory.

Percent

If the AD server is experiencing abnormally high write activity, then, you can compare the value of this measure with the values reported by the DS writes from DRA, DS writes from KCC, DS writes from LSA, DS writes from NSPI, and DS writes from SAM measures to know which AD service is performing the maximum writes on the AD server - is it the replication service? the LSA? the KCC? the NSPI? the NTDS? or the SAM?

DS writes from SAM

Indicates the percentage of writes performed by the Security Accounts Manager (SAM) on the directory.

Percent

If the AD server is experiencing abnormally high write activity, then, you can compare the value of this measure with the values reported by the DS writes from DRA, DS writes from KCC, DS writes from LSA, DS writes from NSPI, and DS writes from NTDS measures to know which AD service is performing the maximum writes on the AD server - is it the replication service? the LSA? the KCC? the NSPI? the NTDS? or the SAM?

DS searches from DRA

Indicates the  percentage of searches performed by the replication service on the AD server.

Percent

If the AD server is processing an abnormally large number of search requests, then, you can compare the value of this measure with the values reported by the DS searches from KCC, DS searches from LSA, DS searches from NSPI, DS searches from NTDS, and DS searches from SAM measures to know which AD service is performing the maximum number of searches on the AD server - is it the replication service? the LSA? the KCC? the NSPI? the NTDS? or the SAM?

DS searches from KCC

Indicates the percentage of searches performed by the Knowledge Consistency Checker on the directory.

 

Percent

If the AD server is processing an abnormally large number of search requests, then, you can compare the value of this measure with the values reported by the DS searches from DRA, DS searches from LSA, DS searches from NSPI, DS searches from NTDS, and DS searches from SAM measures to know which AD service is performing the maximum number of searches on the AD server - is it the replication service? the LSA? the KCC? the NSPI? the NTDS? or the SAM?

DS searches from LSA

Indicates the percentage of searches performed by the Local Security Authority on the directory.

 

Percent

If the AD server is processing an abnormally large number of search requests, then, you can compare the value of this measure with the values reported by the DS searches from DRA, DS searches from KCC, DS searches from NSPI, DS searches from NTDS, and DS searches from SAM measures to know which AD service is performing the maximum number of searches on the AD server - is it the replication service? the LSA? the KCC? the NSPI? the NTDS? or the SAM?

DS searches from NSPI

Indicates the percentage of searches performed by the Name Service Provider Interface (NSPI) on the directory.

Percent

If the AD server is processing an abnormally large number of search requests, then, you can compare the value of this measure with the values reported by the DS searches from DRA, DS searches from KCC, DS searches from LSA, DS searches from NTDS, and DS searches from SAM measures to know which AD service is performing the maximum number of searches on the AD server - is it the replication service? the LSA? the KCC? the NSPI? the NTDS? or the SAM?

DS searches from NTDS

Indicates the percentage of searches performed by the name service directory APIs on the directory.

Percent

If the AD server is processing an abnormally large number of search requests, then, you can compare the value of this measure with the values reported by the DS searches from DRA, DS searches from KCC, DS searches from LSA, DS searches from NSPI, and DS searches from SAM measures to know which AD service is performing the maximum number of searches on the AD server - is it the replication service? the LSA? the KCC? the NSPI? the NTDS? or the SAM?

DS searches from SAM

Indicates the percentage of searches performed by the Security Accounts Manager (SAM) on the directory.

Percent

If the AD server is processing an abnormally large number of search requests, then, you can compare the value of this measure with the values reported by the DS searches from DSA, DS searches from KCC, DS searches from LSA, DS searches from NSPI, and DS searches from NTDS measures to know which AD service is performing the maximum number of searches on the AD server - is it the replication service? the LSA? the KCC? the NSPI? the NTDS? or the SAM?