Exchange 2013 Move/Migrate all mailboxes to new DAG

Jack Chuong 856 Reputation points
2021-03-24T09:06:54.023+00:00

Hi all,
My environment : 3 Exchange 2013 CU23 servers (both CAS + Mailbox roles) in 1 DAG , Windows server 2008 R2 : ex01 , ex02 , ex03 .
ex01 and ex02 are same hardware configuration.
ex03 hardware is more powerful then ex01 and ex02

I'm going to purchase a new server (ex04) with same hardware as server ex03 and I attempt to restructure my Exchange environment : 2 Exchange 2013 CU23 servers (both CAS + Mailbox roles) in 1 DAG , Windows server 2012 R2 : ex03 , ex04

I do some search:

  • Exchange 2013 support OS to Window Server 2012 R2
  • We cannot perform a in-place upgrade of operation system from Windows server 2008 R2 to Windows server 2012 R2 on a server running Exchange 2013
  • all the servers in the DAG have to be the same O/S

So I have to Move/Migrate all mailboxes from DAG1 (ex01 , ex02) to DAG2 (ex03 , ex04):

  • Remove all the databases from Ex03 and remove the server from the current DAG
  • Rebuild Ex03 with 2012R2
  • Then create a new DAG with Ex03 and Ex04 running the same O/S and create new databases and replicate them between the 2 servers
  • Move mailboxes from EX01 and Ex02 to the new servers (03/04) ( including arbitration mailboxes!)
  • Remove the old databases on 01 and 02 when everything is moved and remove the servers from the old DAG
  • Remove the old DAG

I have some concerns :

  • I have 1000+ mailboxes distributed through 7 databases , hosting email for multiple domains.
  • I have SAN cert with multiple Subject Alt Names : webmail.mydomain.com , autodiscover.domain1.com , autodiscover.domain2.com ... set up on current DAG
  • It takes about 2 weeks to move all mailboxes from old DAG to new one.
  • New DAG and Exchange servers (ex03 , ex04) are same Active Directory domain with old DAG (ex01 , ex02)
    --> I can setup Virtual Directory URLs , IIS certificate on new DAG same as old DAG, add A record for webmail.mydomain.com , autodiscover.domain1.com , autodiscover.domain2.com ... point to ex03 , ex04 IP addresses also ?

--> MS Outlook on users computers will connect to new Mailbox servers after Migration Batches complete ? (Because user mailbox's information stored at Active Directory will be updated automatically)

Users can use email normally when Migration Batches running ? Will they notice any interruptions/downtime ?
How about arbitration mailboxes ? This is my arbitration mailboxes : 

     Get-MailboxDatabase | Get-Mailbox -Arbitration | fl Name,ServerName,Database  
          
     Name       : SystemMailbox{bb558c35-97f1-4cb9-8ff7-d53741dc928c}  
     ServerName : ex01  
     Database   : Mailbox Database 1  
          
     Name       : SystemMailbox{1f05a927-38a2-412b-9fd4-3f182479f5f7}  
     ServerName : ex01  
     Database   : Mailbox Database 1  
          
     Name       : SystemMailbox{e0dc1c29-89c3-4034-b678-e6c29d823ed9}  
     ServerName : ex01  
     Database   : Mailbox Database 1  
          
     Name       : Migration.8f3e7716-2011-43e4-96b1-aba62d229136  
     ServerName : ex01  
     Database   : Mailbox Database 1  
          
     Name       : FederatedEmail.4c1f4d8b-8179-4148-93bf-00a95fa1e042  
     ServerName : ex01  
     Database   : Mailbox Database 1

Should I move them at first or last after all mailboxes are moved ?
How about the Recoverable Items folder ? Will it be moved together with mailbox ?

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.
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  1. KyleXu-MSFT 26,206 Reputation points
    2021-03-25T02:57:15.973+00:00

    @Jack Chuong

    I can setup Virtual Directory URLs , IIS certificate on new DAG same as old DAG, add A record for webmail.mydomain.com , autodiscover.domain1.com , autodiscover.domain2.com ... point to ex03 , ex04 IP addresses also ?

    After configuring service URLs for new DAG server, you can switch DNS from old one to new one directly. Don't need to create new DNS record for new Exchange server. You cannot point one record to two IP addresses. Personally, you can switch DNS record at the last step, before that, client request could redirect from old one to new one.

    MS Outlook on users computers will connect to new Mailbox servers after Migration Batches complete ? (Because user mailbox's information stored at Active Directory will be updated automatically)

    During migration, user still could using their mailboxes. After migrating complete, they will get a pop-up like below:
    81381-qa-kyle-10-49-29.png
    After restart Outlook, they will could connect to new Exchange server. Sometimes, users may need to reconfigure Outlook profile.

    Should I move them at first or last after all mailboxes are moved ?

    Before migrating. You can also recreate them on new Exchange server directly.

    How about the Recoverable Items folder ? Will it be moved together with mailbox ?

    It hosted on mailbox.

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  1. Jack Chuong 856 Reputation points
    2021-03-25T03:44:46.32+00:00

    Hi KyleXu, thanks for your reply.
    So Recoverable Items folder , interruptions/downtime concerns are temporarily put aside .
    About Virtual Directory URLs :

    You cannot point one record to two IP addresses

    I can do that, for now , webmail.mydomain.com is point to 3 Ex server IP addresses (even so autodiscover.domain1.com , autodiscover.domain2.com ...) , they work fine.

    I think I have 3 options here :

    1. Create new DNS record (autodiscover , owa , ews , ecp , oab , activesync ...) for new Exchange servers
    2. Switch DNS from old one to new one right after configuring service URLs for new DAG server
      --> the user has not been moved will use CAS on new Exchange servers (ex3 , ex4) , connect to database on old Exchange servers (ex1 , ex2)
      --> the user has been moved will use CAS and connect to database on new Exchange servers (ex3 , ex4)
    3. Switch DNS record at the last step
      --> the user has been moved will use CAS on old Exchange servers (ex1 , ex2) , connect to database on new Exchange servers (ex3 , ex4)
      --> the user has not been moved will use CAS and connect to database on old Exchange servers (ex1 , ex2)

    About arbitration mailboxes , I don't want to recreate them on new Exchange server. As I now there are 5 arbitration mailboxes created by default when installing Exchange first time , 1 mailbox is for generating GAL/OAB , 4 others mailboxes are for other reasons ...
    When installing new Exchange server I won't run "Setup.exe /PrepareAD /IAcceptExchangeServerLicenseTerms" so they won't recreate 5 arbitration mailboxes , so :
    --> If I switch DNS from old one to new one right after configuring service URLs for new DAG server , the user has been moved will use CAS and connect to database on new Exchange servers (ex3 , ex4) --> they don't have GAL/OAB ?
    --> I should switch DNS record at the last step (after all mailboxes are moved , arbitration mailboxes are moved) so the user has been moved will use CAS on old Exchange servers (ex1 , ex2) and they can use GAL/OAB normally ?