How to temporarily increase the Exchange 2000 16-gigabyte database size limit

The Microsoft Exchange 2000 Server Standard Edition Information Store automatically shuts down and will not restart when it reaches the maximum permitted size limit. Additionally, the following event IDs may be logged in the Application event log:

Event Type: Error
Event Source: MSExchangeIS
Event Category: General
Event ID: 1112
Description: The database "Mailbox Store ( Server Name )" has reached the maximum allowed size. Attempting to unmount the database.

Event Type: Warning
Event Source: ESE
Event Category: Space Management
Event ID: 445
Description: Information Store (3160) The database D:\Program Files\Exchsrvr\MDBDATA\priv1.edb has reached its maximum size of 16383 MB. If the database cannot be restarted, an offline defragmentation may be performed to reduce its size.

Note Although the description for event ID 445 states that the Priv1.edb file has reached a size of 16,383 megabytes (MB), this may not be true. Event ID 445 is triggered if the combined size of the Priv1.edb file and the Priv1.stm file reaches 16,383 MB. The Priv1.edb file by itself may be smaller than 16,383 MB.

This behavior is by design to prevent an Exchange Server 2000 Standard Edition Information Store database from trying to insert more data into the database file than it was designed to hold.

Frequently, you experience this behavior when you are running Microsoft Exchange 2000 Server Standard Edition. Exchange 2000 Server Standard Edition limits the database size to 16 gigabytes (GB).

Note The 16-GB size limit for the Exchange private mailbox store database and the 16-GB size limit for the Exchange public mailbox store database is the sum of the size of both the Priv.edb and the Priv.stm files. When you view the space that a mailbox uses in Exchange System Manager, the amount only includes the space that is used by the Priv.edb file. The amount does not include the space that the Priv.stm file uses.

When you put a limit on a mailbox, you only limit the storage in the Priv.edb file. You do not limit the storage in the Priv.stm file. For example, a mailbox may appear to use only 250 MB of space in Exchange System Manager. However, the total space that the mailbox uses may be 450 MB. This difference occurs because the 200 MB of space that the Priv.stm file uses does not appear in Exchange System Manager.

A new update to Exchange 2000 Server Standard Edition has been developed. This update lets you temporarily increase the database size limit by 1 GB.

To resolve this issue, the administrator must perform the following tasks:

• Temporarily increase the database size limit by 1 GB.
• Selectively remove unnecessary database content.
• Defragment the database to reduce the database to a level that is in the defined boundaries of the database size.

In Exchange Server 2003, the functionality to temporarily increase the database size limit by 1 GB is built into the product. However, to enable this functionality, the administrator must create the new registry value that is mentioned in the following Knowledge Base article:

To resolve this issue in Exchange 2000, you can apply the September 2003 Exchange 2000 Server post-Service Pack 3 Rollup. Then the administrator must create the new registry value to enable this feature. For additional information about how to download and install the rollup, click the following article number to view the article in the Microsoft Knowledge Base:
If you are plan to install the September 2003 Exchange 2000 Server post-Service Pack 3 Rollup later, but you require a fix for this issue now, read the following Update information" section.

Update Information

A supported feature that modifies the default behavior of the product is available from Microsoft. However, this feature is intended to modify only the behavior that this article describes. Apply this feature only to systems that specifically require it.

If the feature is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the feature.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific feature. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the feature is available. If you do not see your language, it is because the feature is not available for that language.

Prerequisites

Because of file dependencies, this update requires Microsoft Exchange 2000 Server Service Pack 3 (SP3). For more information, click the following article number to view the article in the Microsoft Knowledge Base:

File Information

The English version of this update has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

Create New Registry Value

The update requires you to create a new registry value to enable this feature.

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:

To add the registry entry to the Exchange 2000 computer, follow these steps:

1. Click Start, click Run, and then type regedt32.exe.
2. Locate the following key in the registry: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIS\<Exchange Server Name>\Private-<long hexadecimal string>
3. On the Edit menu, click Add Value, and then type the following in the Value name box: Temporary DB Size Limit Extension
4. Select REG_DWORD for the data type, and then click OK.
5. Enter a value of 1, and then click OK.
6. Quit Registry Editor.

If the Temporary DB Size Limit Extension registry value exists for a specific database and if the value is set a value other than zero, the database size limit (if any) is increased by 1 gigabyte. However, this registry value is not read dynamically; it is only read when a database is started. When the Exchange Information Store starts, an event 9657 will be logged as a warning to inform you that you are using a temporary database size limit.

Note To prevent new e-mail content from being added to the mailbox store beyond the temporary 17-GB limit during the recovery process, we strongly recommend that you stop the Simple Mail Transfer Protocol (SMTP) service and the Microsoft Exchange MTA Stacks service before you mount the mailbox store. For more information about how to remove unnecessary database content and how to defragment the database, click the following article number to view the article in the Microsoft Knowledge Base:

This behavior is by design. However, the update that is described in this article modifies the designed behavior.