The logical size of this database is 18Gb This database size has exceeded the size limit of 18 GB

Microsoft exchange ceases receiving e-mails and you seen an event log errors such as:

Event Type: Error
Event Source: MSExchangeIS Mailbox Store
Event Category: General
Event ID: 9690
Date:  23/08/2009
Time:  5:00:45 AM
User:  N/A
Computer: EXCHANGE
Description:
Exchange store ‘First Storage Group\Mailbox Store (EXCHANGE)’: The logical size of this database (the logical size equals the physical size of the .edb file and the .stm file minus the logical free space in each) is 18 GB. This database size has exceeded the size limit of 18 GB.

This database will be dismounted immediately.

Event Type: Error
Event Source: MSExchangeSA
Event Category: MAPI Session
Event ID: 9175
Date:  23/08/2009
Time:  4:17:45 PM
User:  N/A
Computer: EXCHANGE
Description:
The MAPI call ‘OpenMsgStore’ failed with the following error:
The attempt to log on to the Microsoft Exchange Server computer has failed.
The MAPI provider failed.
Microsoft Exchange Server Information Store
ID no: 8004011d-0512-00000000

 

 

To change the default store size from 18gb to 50gb and set the warning when IS nears maximum size do the following:

 

• Open registry editor
• Navigate to
  HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIS\<SERVER NAME>\Private-{code}
• Create Key REG_DWORD Database Size Limit in GB e.g. to increase size of IS to 50GB set value to 50 (0×00000032)
• Create Key REG_DWORD Database Size Buffer Warning in Percentage
  e.g. Create key for warning when IS has less than 10% space remaining set value to 10 (0×0000000a)
• Restart IS
•  
• Check Application log for message indicating size change.