exchange database have automatic switch over

Louis Ruth 1 Reputation point

the event log as below

A request to mount Active or Passive database was processed in 0.0214939 seconds.

Flags: 0x00000008
Error code: NoError (0x00000000)

Information Store - (47140,R,0,15.01.1779.002) The database engine has begun replaying logfile E:\Program Files\Microsoft\Exchange Server\V15\Mailbox\database\E04.log.

Previous Log Processing Stats:
1 395.168726 -2.929166 (1584) CM +J(CM:1584, PgRf:329433, Rd:3696/31, Dy:3782/520119, Lg:139787869/556120) +M(C:1341976K, Fs:237443, WS:363016K # 348824K, PF:1381028K # 1367372K, P:1381028K).

Then run a log to copy to E drive
“Information Store - MBX - Senior01 (47140,R,0,15.01.1779.002) MBX - Senior01: The database engine has begun replaying logfile E:\Program Files\Microsoft\Exchange Server\V15. “

how to avoid this status , because when failover to other database , around 1 hr the database will auto switch to original database and mounted back

is it the right not good or other possible reason

it is too trouble because the status happen the user outlook will no response and hang

Exchange Server Management
Exchange Server Management
Exchange Server: A family of Microsoft client/server messaging and collaboration software.Management: The act or process of organizing, handling, directing or controlling something.
7,390 questions
0 comments No comments
{count} votes

13 answers

Sort by: Most helpful
  1. Xzsssss 8,861 Reputation points Microsoft Vendor

    Hi @Louis Ruth ,

    Good day!
    What’s the version of your Exchange server?

    If it’s Exchange 2016 CU2 and later version(include Exchange 2019), that could make sense.
    Since after Exchange 2016 CU2, the new property PreferenceMoveFrequency was added:
    You could disable this feature with this cmdlet:
    Set-DatabaseAvailabilityGroup -Identity DAG01 -PreferenceMoveFrequency ([System.Threading.Timeout]::InfiniteTimeSpan)


    If the response is helpful, please click "Accept Answer" and upvote it.
    Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

  2. Louis Ruth 1 Reputation point

    how to disable PreferenceMoveFrequency feature

    and i check C:\ExchangeSetupLogs\DagTasks no location here.

  3. Louis Ruth 1 Reputation point


    default is 1:00:00

    i check have event log

    1. Event code: 3005
      Event message: An unhandled exception has occurred.
      Event time:
      Event time
      Event ID: 42711299724e498d904aae658dfd1ff6
    2. Re-delivery of messages from the transport dumpster will be attempted for database . Messages originally delivered between 2/10/2021 and 2/10/2021 3:45:25 AM (UTC) will be re-delivered.
    3. Cannot access file, the file is locked or in use [HResult: 0x80131500]. The copier will automatically retry after a short delay.

    then auto switch database to server B

    how to avoid this status happen

  4. Louis Ruth 1 Reputation point

    the copy of database 'XX' on this server appears to be experiencing performance issues, possibly as a result of storage failure. Consult the event log on the server for other storage and "ExchangeStoreDb" events for more specific information about the failure. Recovery was not attempted.

    also happen database auto switch

  5. Louis Ruth 1 Reputation point

    Get-MailboxDatabaseCopyStatus *
    have no failed

    but always show other Exchange B mounted default on Exchange A database

    after 1 hr , Database willauto change back Exchange A mounted , it's too confused

    during switch database , user outlook will hang and email will show disconnect with exchange