HI All,

I am In trouble..... Need your help...

In my Org, we are using Exchange server 2013 (recently migrated)

Since few Months we are having big problem with the DBs.

Every week Monday Early morning around 3AM to 4AM most of all the DBs are getting failover 

When look into the event logs, it says only....

Event ID 3008

[Eas] Failed to refresh Mailbox server for database *******-07b9-43**-874d-174*****d9 in resource forest (Domain name). Exception: Microsoft.Exchange.Data.Directory.ADTransientException: Could not find any available Domain Controller.
   at Microsoft.Exchange.Data.Directory.ConnectionPoolManager.GetConnection(ConnectionType connectionType, String partitionFqdn, ADObjectId domain, String serverName, Int32 port, NetworkCredential credential)
   at Microsoft.Exchange.Data.Directory.ConnectionPoolManager.GetConnection(ConnectionType connectionType, String partitionFqdn)
   at Microsoft.Exchange.Data.Directory.ADDataSession.GetConnection(String preferredServer, Boolean isWriteOperation, String optionalBaseDN, ADObjectId& rootId, ADScope scope)
   at Microsoft.Exchange.Data.Directory.ADDataSession.GetReadConnection(String preferredServer, String optionalBaseDN, ADObjectId& rootId, ADRawEntry scopeDeteriminingObject)
   at Microsoft.Exchange.Data.Directory.ADDataSession.InternalFind[TResult](ADObjectId rootId, String optionalBaseDN, ADObjectId readId, QueryScope scope, QueryFilter filter, SortBy sortBy, Int32 maxResults, IEnumerable`1 properties, Boolean includeDeletedObjects)
   at Microsoft.Exchange.Data.Directory.ADDataSession.Find[TResult](ADObjectId rootId, QueryScope scope, QueryFilter filter, SortBy sortBy, Int32 maxResults, IEnumerable`1 properties, Boolean includeDeletedObjects)
   at Microsoft.Exchange.Data.Directory.ADDataSession.Find[TResult](ADObjectId rootId, QueryScope scope, QueryFilter filter, SortBy sortBy, Int32 maxResults)
   at Microsoft.Exchange.Data.Directory.SystemConfiguration.ADTopologyConfigurationSession.<>c__DisplayClass1f`1.<FindDatabaseByGuid>b__1e()
   at Microsoft.Exchange.Data.Directory.Diagnostics.ADScenarioLog.InvokeWithAPILog[T](DateTime whenUTC, String name, Guid activityId, String implementation, String caller, Func`1 action, Func`1 getDcFunc)
   at Microsoft.Exchange.Data.Directory.SystemConfiguration.ADTopologyConfigurationSession.InvokeWithAPILogging[T](Func`1 action, String memberName)
   at Microsoft.Exchange.Data.ApplicationLogic.Cafe.MailboxServerLocator.<ResolveMasterServerOrDag>b__11()
   at Microsoft.Exchange.Data.ApplicationLogic.Cafe.MailboxServerLocator.InvokeResourceForest[T](Func`1 adCall)
   at Microsoft.Exchange.Data.ApplicationLogic.Cafe.MailboxServerLocator.ResolveMasterServerOrDag()
   at Microsoft.Exchange.Data.ApplicationLogic.Cafe.MailboxServerLocator.BeginGetServer(AsyncCallback callback, Object asyncState)
   at Microsoft.Exchange.HttpProxy.MailboxServerCache.RefreshDatabase(DatabaseWithForest database)

We are unable to find the cause for this issue..

AD issue may not be possible because we have a redundancy  and all other applications (other than exchange) are working fine..

I also want to know, whether this logs will generate after the DB fail over or due to some issue DB will fail over and this logs will generate??(To narrow down the investigation)

Could any one help in this to resolve the weekly happening DB fail over issue?

Also let me know any information is required.

Thank you, 

Pradeep

• Moved by Jason Johnston [MSFT]Microsoft employee 15 hours 14 minutes ago Not a development question.

This forum is for Exchange Development questions. This question seems to be more about Exchange Administration, and would be better served in the Exchange Administration forum on TechNet. I'll move it over for you.