Upgradation global catalog

Question

Should servers which are executing Active Directory domain controllers and the global catalog be upgraded to the 64-bit?

Answer 1

For the better performance, when an Active Directory organization holds more than 20,000 objects, you must upgrade to 64-bit. Upgrading servers which run Active Directory domain controllers and the global catalog to the 64-bit enhance the entire scalability and performance of your Exchange Server 2007 environment. But, 32-bit domain controllers are still supported.

Lookup and response times among the Exchange 2007 categorizer and the Active Directory service will enhance with the employ of 64-bit. The size of the Extensible Storage Engine (or ESE) database which contains Active Directory can frequently be greater than 3.0 gigabytes (or GB). This prevents caching of contents of the entire database, and thus raises lookup and response times. By using 64-bit, the accessible RAM for caching can be raised beyond 4.0 GB. This is large sufficient to cache the entire ESE database, even for big Active Directory organizations, and will enhance Exchange 2007 lookup and response times.