The Exchange SP2 became available for download yesterday. Even though Exchange 2003 has been very stable for us, SP2 is already installed on the test server here and I’ve been doing some reading to determine how soon we’ll need to install it. The biggest positive I’ve found yet is the increase in the mail database limit to 75GB on the Standard version of Exchange 2003. This is a much-needed increase, and the only reason we’re running Exchange’s expensive Enterprise version is our need to accomodate huge attachements from cour clients. I also have a personal client in television-services who will be thrilled to know their four users can now store video clips in exchange, instead of constantly archiving to one big folder on the network.

The 75GB database limit isn’t set automatically when SP2 is installed. After all, 75GB exceeds a lot of expectations of the Exchange server and the disk space on most older servers. Since so few admins read the documentation, they might miss this change and lock up their servers. The registry change below, originally explained by The Lazyadmin.com can be set to any value between 1 and 75, the maximum size of the Exchange database in GB’s. By default Exchange 2003 SP2 pushes the default database size to about 18GB, which is the original 16GB maximum plus a 10% over-limit buffer to keep mail coming in while Exchange floods the system with alerts about the database size.

To expand the Exchange database, or set a limit between 1 & 75GB:

1. Open regedit and navigate to HKLM\SYSTEM\CurrentControlSet\Services\MSExchangeIS\SERVER_NAME\Private-STORE_GUID. To change the Public store limit, navigate to HKLM\SYSTEM\CurrentControlSet\Services\MSExchangeIS\SERVER_NAME\Public-STORE_GUID.
2. In the event your Exchange server has more than one private or public store the GUID of each store can be found by running ADSIEDIT.msc and navigating to:
   

   CN=MAILBOX_STORE_NAME (SERVER_NAME),CN=STORAGE_GROUP_NAME,CN=InformationStore,CN=SERVER_NAME,CN=Servers,CN=First Administrative Group,CN=Administrative Groups,CN=Organization name,CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=domain,DC=com

   SERVER_NAME, STORAGE_GROUP_NAME, and MAILBOX_STORE_NAME reflect the mail store to be changed. Then take note of the objectGUID:… value for that mail store.

3. Create a new REG_DWORD value in the registry key for the correct GUID. Name it “Database Size Limit in Gb” and set the value from 1 to 75.
4. Assuming you are newly setting the “Database Size Limit in Gb” value, it will be detected at the next size check. Reboot the Information Store service for immediate recognition.

By setting the “Database Size Limit in Gb” key the mailbox store will not exceed that value. When the mail store reaches 90% off that value, a default 10% buffer is allowed, it will begin to log event ID #9689 to notify you that the store limit has been reached. Once the mail store does reach the maximum limit the first size check, which happens every 24 hours at 5am, will not take the database offline. The second size check will dismount the store that exceeds the limit.

Both the % of the mail store used as a buffer and the time of the database size check can be changed within the same GUID registry key referenced above. To set either, create a REG_DWORD value named “Database Size Buffer in Percentage” or “Database Size Check Start Time in Hours From Midnight”. Set their values from 1 to 100 or 0 to 23 to change, respectively, the buffer % or the offset from midnight for the size check.

The Exchange 2003 Enterprise information store can also be limitted by the “Database Size Limit in Gb” key. The valid range of values is 1 to 8000. If the key is not set, the default value is 8000GB.

It still amazes me that the Exchange System Manager doesn’t have settings for either “max. database size” or “min. disk space remaining on server”. Isn’t that the whole point of Exchange? …that it’s faster and easier to run because it doesn’t require the amount of experience and forethought that Postfix does.

Update: This same registry tweak is also supported on Windows Small Business Server 2003 (SBS). See the comments below for a link the the SBS 2003 FAQ.

9 Responses to “Registry Tweak to set a 75GB Store Limit on Exchange 2003 Standard SP2”

1. Joachim Otahal, on February 17th, 2006 at 12:45 am, said:
   

   Does this registry tweak work on Small Business 2003 too if EXSP2 is installed?

2. Mike Bijon, on February 17th, 2006 at 5:03 pm, said:
   

   Yes, this registry tweak DOES allow you to increase the storage limit on Windows SBS 2003 also. From Microsoft’s SBS 2003 FAQ:

   Q. How will the change in the Exchange Server 2003 storage limit affect Windows SBS 2003?

   A. Windows SBS 2003 customers can take advantage of the storage limit changes implemented in Exchange Server 2003 SP2.

3. John McKenney, on March 18th, 2006 at 8:06 am, said:
   

   When you create the reg_dword should the 1 - 75 be entered as hex or decimal

4. Mike Bijon, on March 18th, 2006 at 4:01 pm, said:
   

   If you use decide to use decimal then enter 1 - 75. If you use hex then enter 1 - 4B.

   -Mike, “Mr. Tweak”

5. Corbin, on September 19th, 2007 at 8:17 am, said:
   

   I can’t thank you enough for putting this explanation together.

   Since this things seems to grow huge(75gig limit) is there a way to purge or compact it?

6. rikki, on November 12th, 2007 at 8:27 am, said:
   

   A couple of easy things you can perform to limit the size, lower the deleted items retention from 30 days to 7 days, I actually got ours set to 3 days, run the clean up agent to get rid of any deleted users mailboxes still on your information store once you’ve done that check the size of your database the following in event viewer to see how much space the online defrag reclaimed. Finally you can schedule an offline defrag to get more free space in your DB, obviously this should be done out of hours to minimize business impact.

7. sami, on February 20th, 2008 at 12:04 am, said:
   

   i did all u said but still cant mount the database it gives an error .

8. Admin Rotter, on March 16th, 2008 at 8:05 pm, said:
   

   how can you reduce the stm file?

9. MS exchange server « Libitt’s Weblog, on April 16th, 2008 at 12:24 pm, said:
   

   […] Registry tweak to set a 75gb store limit on Exchange 2003 Standard Sp2. Retrieved on […]

Comment on this post below

You can leave a response, or trackback from your own site.