Setting the Computer Retrieval Method


Computer Retrieval Background

Exporter Pro now includes an option to determine the method used to retrieve domain computer accounts. To better understand this important option, it helps to better understand the problem of retrieving, accessing, and filtering computers.  

Why Computer Accounts are Needed

Exporter needs to retrieve a list of computer accounts for any Domain or Active Directory OU object that is added and enabled for the export object list, provided that one or more "computer" export options have been selected.  Examples of computer export options are services and disk space or anything, for example, that must be requested directly from a remote computer.  Since domains and OUs can contain computers, when they are encountered in an export configuration, Exporter must extract the computer list so that it can export other items as specified in the configuration.   Note: If computer accounts are entered manually into Exporter's object list, this retrieval procedure does not apply.

Where Computer Accounts are Stored

Computer account information can be found in two (2) places in Windows:

1.  The SAM/Active Directory.  Both Windows NT and Windows 2000/2003 domains maintain a 'master' list of computer accounts.  These are computer accounts that have been added into the domain.  In many domains, this list can contain a number of obsolete, test, or special-purpose computer accounts as well as the standard workstation and server computer accounts.  For Windows NT, this list is kept in the SAM, along with user and group information.  For Windows 2000/2003 domains, the computer list is part of Active Directory.  The advantages of using the SAM/Active Directory for the list of computers is that the list will be 100% accurate and complete.  The disadvantage is that it may be TOO complete and cause delays in exporting information as old or inaccessible computers are encountered.  This master list also does not store any information about what roles (domain controller, server, print server) the computer participates in.

2. The Windows browse list.  The Windows browse list has been around for a very long time.  If enabled and permitted for a particular network environment, computers announce themselves when they are turned on, and Windows adds the computer name to a retrievable list (the browse list).  The computers also announce their associated comment and roles (domain controller, server, print server, etc.) to the browse list as well.  The advantages of using the browse list for a list of computers is that it is very fast to retrieve, contains information about the types of computers, and is usually 90% + accurate (if available at all).  The disadvantage is that the browse list can be not available at all, only partially accurate, and is never/rarely 100% accurate.

Performance Implications

The impact of whether to retrieve the computer list from the SAM/Active Directory or from the Windows browse list can impact exporting performance, sometimes significantly.  The amount of performance impact will depend upon how many computers are in the network environment and how many of them are offline/non-existent.  Using the Windows browse list will result in the least amount of offline computers, since computers are removed from the browse list automatically after a short time when they are removed from the network.  

Setting the option to ping a remote computer before attempting remote access can improve performance regardless of which computer retrieval option is used.

How to Specify the Computer Retrieval Method

To specify which method is to be used to retrieve the computer accounts, select Configuration Properties->Export Properties->General.  The default method is to use the Windows browse list.

It is recommended that both methods be tried to see which procedure provides the best fit to accuracy vs. performance.