XADM: Factors That Determine the Size of the Directory Database

SUMMARY

The size of the Microsoft Exchange Server directory database depends on the following factors:

• Which Address Book fields are populated for each entry. This includes fields such as the address and phone number fields. In general, if more fields are populated, the Address Book entry is larger.
  
  
• The number of distribution lists (DLs) that exist and the number of members in each DL.
  
  
• The number of languages that the Microsoft Exchange Server computer supports.

In addition, DLs are larger than mailboxes and mailboxes are larger than custom recipients, so the exact composition of the directory database can be a factor.

In general, each directory database entry is between 2-5K in size.