Applies to: Exchange Server 2010 SP3, Exchange Server 2010 SP2

Topic Last Modified: 2010-07-29

An indication of an unhealthy Exchange store is that threads are either deadlocked or are otherwise not making progress. If there are more than five threads on a single mailbox, ten threads on a single database, or twenty threads on a single server that haven't progressed in one minute, a time-out is reported on the server. The performance counters that indicate time-outs are:

• RPC Request Timeout Detected on Mailbox
  
  
• RPC Request Timeout Detected on Database
  
  
• RPC Request Timeout Detected on Server
  
  

The Exchange store also writes the following events to the server under the MSExchangeIS source:

• Event 10025   Reports a time-out on the Exchange server
  
  
• Event 10026   Reports a time-out on the database
  
  
• Event 10027   Reports a time-out on an individual mailbox
  
  

If the time-out is detected on a single mailbox, the mailbox is potentially considered to be poisoned and is handled similarly to a failure by increasing the CrashCount property. This action makes the mailbox susceptible to being quarantined. Therefore, you may want to turn off Exchange store time-out detection for Mailbox servers that regularly have a large number of threads operating against them.

Use the Registry to turn off Exchange store time-out detection

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