Exchange 2003 Enterprise Mailbox Size Maximums

Posted on 2005-04-08
Medium Priority
Last Modified: 2008-03-17
Done some digging and I can see that older versions of Outlook has limitations on the maximum PST size (but not Outlook 2003), and that Exchange Standard had the 16GB mailbox limit.

However, what I haven't been able to find out was if there were any actual limits to the size of a mailbox in Exchange 2003 Enterprise.  I've got a couple of users that require a considerable amount of email in their mailbox all the time (primarily Human Resources people).

So, if someone could provide an answer as to whether or not Exchange Enterprise 2003 has any limits on mailbox size, that would be great.  Thanks.
Question by:lrees
LVL 25

Accepted Solution

mikeleebrla earned 136 total points
ID: 13739180
Actually outlook 2003 has a default PST size limit of 20GB but you can change this.
As far as the size of a mailbox on the server, this is mainly limited by the amount of hard drive space on your server where the exchange database is kept.  There might be some maximum, but whatever it is it would be VERY large and you would never get to this limit. How big are the mailboxes in question?
LVL 20

Assisted Solution

ikm7176 earned 132 total points
ID: 13743496
Enterprise Edition Features

The following feature enhancements are included in Exchange Server 2003 Enterprise Edition:

-  Exchange 2003 Enterprise Edition supports up to four storage groups, with each storage group having up to five databases.
-  Database size is limited only by hardware (with a maximum size of 16 terabytes).
-  Exchange 2003 Enterprise Edition can be clustered on the Microsoft Cluster Server cluster service.
-  The X.400 connector is included.

Standard Edition Limitations

The following are limitations of Exchange Server 2003 Standard Edition:

-  Exchange 2003 Standard Edition supports only one storage group and that storage group can only contain two databases.

you will find answers to most of your questions here


-  Individual databases are limited to a maximum size of 16 gigabytes.
- Clustering on Microsoft Cluster Server cluster service is not supported.
- The X.400 connector is not included.

Assisted Solution

maytrix earned 132 total points
ID: 13748718
There are still practical limits.  These would have to do with backup, recovery..etc.  In addition, defragmenting the exchange database would be difficult if it becomes too large as well.  Most companies I deal with that have enterprise and very large databases have used some sort of archiving software to help keep the size manageable.

Author Comment

ID: 13764442
So essentially, no, there's no real limit when it comes right down to the actual size of an individual mailbox.  There are limits to the size of the database in Exchange Standard, and with Enterprise one is only limited by the size of the hardware for all intents and purposes.  To answer the question asked, some of the mailboxes in question at the moment are around 500MB.

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