Silly Doubt in Exchange 2010 - Datacenter SwitchOver

Question

Hi Team
i have a very silly doubt in my exchnage 2010 environment with two sites
 two mailbox servers (Site A )  and another two mailbox servers in site B  .All the four mailbox servers is same DAG 
site A mailbox database copies are available in site B and Vice Versa.
in site A , if two mailbox servers is down / not reachable, automatically the database are moved from site A to Site B and mounted over there. and normal mailflow is happening with interruption of few sec / minutes
then why we need Datacenter SwitchOver  and what is is purpose of doing Datacenter SwitchOver and Datacenter SwitchBack, as the mailflow is functioning without any issue
it may be silly , but i would like to be very clear from  top of my head
thanks team

Answer 1

Hi Li, 
Correct , that is not a problem for me now. The problem is below as mentioned 
i just started the datacenter switch over  from one site to another site and unfortunately i have been halted in the initial stage itself in my test environment
Site: Main-Office
One Domain Controller: Indlabbitesdc01.labbites.co.in  - Hosting
DNS Services
One Hub Server: Indlbht01.labbites.co.in  - Witness Server 
2 CAS server (CAS ARRAY) - casarray1.labbites.co.in and casarray2.labbites.co.in
Casarray IP: 172.29.137.50
2 Mailbox Servers – Indlbmb01.labbites.co.in and indlbmb02.labbites.co.in
Dag Name: DAG1
DAG IP: 172.29.137.140
Site: GUINDY-OFFICE
        - No WIteness server in this SIte
One Additional Controller: Labdeldc01.labbites.con.in
One HUB and CAS Server: indlbguex01.labbites.co.in
2 Mailbox servers – indlbgumbx01.labbites.co.in and indlbmb03.labbites.co.in
Both mailbox servers are members in DAG1
As per Plan , DAC is enabled in DAG1 
Next step i shutdown all the servers Site:
Main-Office and trying to open the powershell from one of the mailbox from Site: GUINDY-OFFICE  for issuing the command Run the Stop-DatabaseAvailabilityGroup cmdlet in the shell  and i got
the below error
         VERBOSE:
Connecting to indlbgumbx01.labbites.co.in
[indlbgumbx01.labbites.co.in]
Connecting to remote server failed with the following error message : WinRM cannot proces
s
the request. The following error occured while using Kerberos authentication: There are currently no logon servers available to service the logon request.
 Possible causes are:
  -The user name or
password specified are invalid.
  -Kerberos is used
when no authentication method and no user name are specified.
  -Kerberos accepts
domain user names, but not local user names.
  -The Service Principal
Name (SPN) for the remote computer name and port does not exist.
  -The client and
remote computers are in different domains and there is no trust between the two domains.
 After checking for
the above issues, try the following:
  -Check the Event
Viewer for events related to authentication.
  -Change the authentication
method; add the destination computer to the WinRM TrustedHosts configuration setting or us
e HTTPS transport.
 Note that computers
in the TrustedHosts list might not be authenticated.
   -For more
information about WinRM configuration, run the following command: winrm help config. For more information,
 see the about_Remote_Troubleshooting
Help topic.
    + CategoryInfo
         : OpenError: (System.Manageme....RemoteRunspace:RemoteRunspace) [], PSRemotingTransportExc
   eption
    + FullyQualifiedErrorId
: PSSessionOpenFailed
Exception calling "GetComputerDomain"
with "0" argument(s): "The local computer is not joined to a domain or the domain
 cannot be contacted."
At C:\Program Files\Microsoft\Exchange
Server\V14\bin\ConnectFunctions.ps1:204 char:70
+     [System.DirectoryServices.ActiveDirectory.Domain]::GetComputerDomain
<<<< ().Forest.Name
    + CategoryInfo
         : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId
: DotNetMethodException
Exception calling "GetComputerSite"
with "0" argument(s): "The specified domain either does not exist or could not be c
ontacted.
At C:\Program Files\Microsoft\Exchange
Server\V14\bin\ConnectFunctions.ps1:164 char:92
+     $localSite=[System.DirectoryServices.ActiveDirectory.ActiveDirectorySite]::GetComputerSite
<<<< ()
    + CategoryInfo
         : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId
: DotNetMethodException
Exception calling "FindAll"
with "0" argument(s): "Unknown error (0x80005000)"
At C:\Program Files\Microsoft\Exchange
Server\V14\bin\ConnectFunctions.ps1:253 char:17
+     $search.FindAll
<<<< ()
    + CategoryInfo
         : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId
: DotNetMethodException
You cannot call a method
on a null-valued expression.
At C:\Program Files\Microsoft\Exchange
Server\V14\bin\ConnectFunctions.ps1:146 char:33
+      
          $siteName = $siteDN.ToString <<<< ().SubString(3).Split(",")[0]
    + CategoryInfo
         : InvalidOperation: (ToString:String) [], RuntimeException
    + FullyQualifiedErrorId
: InvokeMethodOnNull
WARNING:
No Exchange servers are available in the Active Directory site . Connecting to an Exchange server in another
Active Directory site.
Failed to connect to an
Exchange server in the current site.
Enter
the server FQDN where you want to connect.: lbdeldc01.labbites.co.in
VERBOSE: Connecting to
lbdeldc01.labbites.co.in
[lbdeldc01.labbites.co.in]
Connecting to remote server failed with the following error message : WinRM cannot process t
he request. The following
error occured while using Kerberos authentication: There are currently no logon servers avail
able to service the logon
request.
 Possible causes are:
  -The user name or
password specified are invalid.
  -Kerberos is used
when no authentication method and no user name are specified.
  -Kerberos accepts
domain user names, but not local user names.
  -The Service Principal
Name (SPN) for the remote computer name and port does not exist.
  -The client and
remote computers are in different domains and there is no trust between the two domains.
 After checking for
the above issues, try the following:
  -Check the Event
Viewer for events related to authentication.
  -Change the authentication
method; add the destination computer to the WinRM TrustedHosts configuration setting or us
e HTTPS transport.
 Note that computers
in the TrustedHosts list might not be authenticated.
   -For more
information about WinRM configuration, run the following command: winrm help config. For more information,
 see the about_Remote_Troubleshooting
Help topic.
    + CategoryInfo
         : OpenError: (System.Manageme....RemoteRunspace:RemoteRunspace) [], PSRemotingTransportExc
   eption
    + FullyQualifiedErrorId
: PSSessionOpenFailed
[PS] C:\Windows\system32>