This applies to Exchange 2003 SP2.
Today I had a call from a client complaining that their e-mail would sporadically stop working every day or two. They said that by restarting the server, they could temporarily fix the problem.
I connected up, and took a look at the server’s event viewer application logs, around about the times that the client complained this last happened, which was around 07h30 in the morning. At 05h00 in the morning, when the exchange database runs some checks, I found the problem. A warning event that complains that the exchange logical database is now over the default size allowed. Logical size being the physical size of the .edb and .stm files, less the logical free space (also known as white space). Anyway the defaults size for the entire database is 18GB (16GB + 2GB). We need to adjust these now, as our combined mailboxes and public folders are over the 18GB size limit, or are quite close to breaching the limit. If they are over, then your exchange database would have already dismounted following the next check at 05h00 in the morning. If they have not passed the 18GB limit, then you will probably just be getting warning events at the moment, and should still increase the size limits to avoid any downtime.
This is how…
Open the registry editor – Start – Run, and type : regedit
Click Ok
Now navigate to (Note that the GUID is a unique string of numbers for each server) :
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIS\NameOfYourExchangeServer\Private-GUID
Create a new DWORD entry as follows :
Database Size Limit in GB
Right-click and modify the entry once created, and give it a decimal value of anything between 1 and 75 depending on how many GB you want to limit this size to. Make sure you have enough disk space free on the partition your Exchange database is residing, and then enter something higher than 18. For example I used 60 for 60GB.
Click OK
Now navigate to the next part (This is to modify the public folders database size) :
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIS\NameOfYourExchangeServer\Public-GUID
Do the same as above, by creating the same DWORD value, and give it a size limit (decimal value) higher than the current public database value. For example I used 15 for 15GB.
Click OK.
Now we need to exit the registry editor, and restart the Exchange Information Store.
Go to start – run, and type : services.msc
Press enter, or click OK.
Navigate to the Exchange Information Store service, and right click it. Select the restart option.
Please note that this will now dismount your store. If your mail store is still online, users will be temporarily disconnected while the store re-mounts itself. Once back online, the database sizes will have increased, and you will get some nice notifications in your application log informing you of the new database sizes.