Hello Team

Exchange 2010 , In our DAG database copies, most of the database are getting the bellow event in the event viewer

The Microsoft Exchange Replication service has suspended log replay on database 'EX01' because the current copy queue length of 13 exceeds the threshold of 12. Replay will automatically be resumed when the queue length falls below 5.

i have searched in google,but no expected results around . we have lagged databases copies for 3 days.

is there any value or attribute, that we can the threshold .?

since the lagged copies (Replay Queue length) are more or high , is that expected behavior?

can we do the database re-seeding ?

what is the best way to handle this event ID  4110

ops, we are faced this problem before, so there is no any option to change this value, try to ignore this error. :(

Any change in the networking that have caused the database copy to fall behind? If there was a specific issue that caused it then a reseed may fix it, but if there is something that still affects the bandwidth available for the database copy, then a reseed will only fix it temporarily (the reseed itself may fail).  www.eventid.net has some information about this event.

Hi,

Explanation:

The LogReplayer component of the Microsoft Exchange Replication service includes new logic to suspend log replay if the copy queue length increases beyond a specific threshold. If the number of logs in the copy queue is greater than the number of log files that have been copied to the passive database copy, but not inspected by the passive copy, then the Microsoft Exchange Replication service will suspend log replay for the passive copy and log Warning event 4110 in the event log. When the number of log files in the copy queue drops below the number of non-inspected copied log files, the Microsoft Exchange Replication service will resume replay for the passive copy and log Informational event 4111 in the event log. After the copy queue length drop below the threshold, it will resume the log replay automatically.

We couldn't increasethe the threshold for copy queue length, it is by design.

Possible cause

1. network issue
2. search index

You can try reseeding the DB once and see the results

Suspend-MailboxDatabaseCopy <Database>\<serverName>

Then update 

Update-MailboxDatabaseCopy -Identity <Database>\<serverName> DeleteExistingFiles 

Once you perform above resume DB copy and check the health and see the status for a week or so  
Resume-MailboxDatabaseCopy -Identity <Database>\<serverName>

Best Regards.