Outlook 2010 and DAG Fail-back

ei00004
ei00004 used Ask the Experts™
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I have two Exchange 2010 servers A and B usng a DAG. I can disconnect the NIC cable on Exchange serverA and after waiting a few minutes it will automatically mount the DB on Exchange serverB. Then after waiting a few more minutes more my Outlook client reconnected to the failover Exchange serverB. This is perfect!

Now to fail-back to server A, I right clicked on the mailbox server database and mounted it back on primary ServerA. I then stopped all the Exchange services running on serverB, even thought the Outlook clients can open the database on ServerA, they are accessing the database on ServerA while still connected to ServerB.

How do I get my Outlook cleints to change their DNS connection to ServerB?  Rebooting ServerB does not make the clients connect back to ServerA.
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AkhaterSolutions Architect
Commented:
you are mixing 2 things that are not really related

1) you need DAG for you MAILBOX databases so data is replicated between the 2 servers and you already have that

2) however when outlook and other clients connect they connect to the CAS server and not to the mailbox server for that reason you need to have load balancing of your CAS servers and you do not have that.

if you run Get-MailboxDatabase | fl name,RpcClientAccessServer

you will notice that the RpcClientAccessServer is your second server

you need to load-balance your cas server (you will need an external loadbalancer for this since your cas is installed on your mailbox servers) and then create a cas array with these 2 server finally change the RpcClientAccessServer on your databases to point to your cas array
ei00004Network Administrator

Author

Commented:
The RpcClientAccessServer does show the Outlook clients are connected to ServerB. Why is it when I fail-over from ServerA to ServerB the Outlook clients are also changed to point to ServerB?  Whatever is changing the Outlook clients to point to ServerB is not changing it to point back to ServerA.

How can I manually point my Outlook 2010 clients that are connected to ServerB back to ServerA where the database is now located?
Manpreet SIngh KhatraSolutions Architect, Project Lead
Top Expert 2013
Commented:
Is the ServerA and ServerB as CAS Array and what is the roles of ServerA and B ?
Is there some script and which is the CAS Server set as "RpcClientAccessServer" on the Mailbox Database ?

Set-MailboxDatabase -RpcClientAccessServer ServerA

- Rancy
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AkhaterSolutions Architect

Commented:
changing the rpclcientaccessserver when you have a crash won't help i detailed the steps you should follow to solve your problem
ei00004Network Administrator

Author

Commented:
Is there a cmdlet that will show me if I have a CAS array configured or if just one of the servers is acting as a CAS server?  I don't think we have a script that controls which CAS Server is set as "RpcClientAccessServer" but I will find out.
Manpreet SIngh KhatraSolutions Architect, Project Lead
Top Expert 2013

Commented:
I am not sure of that but as you say if its on ServerA and a failover to ServerB does that happen automatically ?

- Rancy
AkhaterSolutions Architect
Commented:
Get-ClientAccessArray

will return the client access array if existing

Get-MailboxDatabase | fl name,RpcClientAccessServer will retrun all DBs and their Client access server

set-mailboxdatabase dbname -RpcClientAccessServer  balbal

will change it
ei00004Network Administrator

Author

Commented:
Yes, ServerA does failover to ServerB automatically.

Get-ClientAccessArray does not show ServerA or ServerB as being in an array, so we will assume a CAS array is not configured.

ServerB is set as my CAS.

I'm out of the office today, but Monday I will try:
Set-MailboxDatabase dbname  -RpcClientAccessServer ServerA
to see if this points my Outlook clients back to ServerA.
Manpreet SIngh KhatraSolutions Architect, Project Lead
Top Expert 2013

Commented:
If ServerA isnt CAS it cant ever be in that field ... this field is only for CAS installed servers

- Rancy
ei00004Network Administrator

Author

Commented:
Ok, how do I make my Outlook clients access ServerA like they did before I failed over to ServerB ?
Manpreet SIngh KhatraSolutions Architect, Project Lead
Top Expert 2013

Commented:
Is CAS role installed on ServerA ? If so the command i gave and you said you were going to check

- Rancy
ei00004Network Administrator

Author

Commented:
The servers are not configured in a CAS array.
RpcClientAccessServer is set to ServerB
What cmdlet will tell me which server has the CAS role installed?
AkhaterSolutions Architect

Commented:
get-clientaccessserver
Manpreet SIngh KhatraSolutions Architect, Project Lead
Top Expert 2013

Commented:
If this command by Akhater only shows ServerB its cause only ServerB has CAS role installed

- Rancy
ei00004Network Administrator

Author

Commented:
get-clientaccessserver shows ServerA and ServerB both in the list.
AkhaterSolutions Architect

Commented:
No offense but I already answered your question like 3 times already,

from the first post in this thread

you need to load-balance your cas server (you will need an external loadbalancer for this since your cas is installed on your mailbox servers)

then create a cas array with these 2 server

finally change the RpcClientAccessServer on your databases to point to your cas array

Since outlook is already created you will need to manually change it on all clients to use the cas array name instead of serverB
ei00004Network Administrator

Author

Commented:
I appreciate your post, and I get it that I need an external loadbalancer to make the clients automatically connect to the other server when one fails. But that still does not answer why it worked the first time.

At this point all I want to do is manually point my Outlook clients back to ServerA, and you said in your post that
set-mailboxdatabase dbname -RpcClientAccessServer  balbal will change it

So I'm assuming in my case it should be
Set-MailboxDatabase dbname  -RpcClientAccessServer ServerA, but Rancy said that would not work unless ServerA is has CAS install on it.  
get-clientaccessserver shows ServerA and ServerB both in the list,  so excuse me for getting mixed signals here.
Manpreet SIngh KhatraSolutions Architect, Project Lead
Top Expert 2013

Commented:
Ideally it shouldnt work at all yes Failover can only happen if its a CASArray not otherwise so not sure if it was already set to ServerB if you didnt check earlier

- Rancy
AkhaterSolutions Architect

Commented:
Set-MailboxDatabase dbname  -RpcClientAccessServer ServerA

will change the RpcClientAccess to serverA that's perfectly correct.

What do you mean by "it worked the first time"? what first time ?

just note that although Set-MailboxDatabase dbname  -RpcClientAccessServer ServerA
 will change the database RpcClientAccessServer  to serverA outlook clients will still be pointing to serverB
ei00004Network Administrator

Author

Commented:
Very first paragraph:
I have two Exchange 2010 servers A and B usng a DAG. I can disconnect the NIC cable on Exchange serverA and after waiting a few minutes it will automatically mount the DB on Exchange serverB. Then after waiting a few more minutes more
my Outlook client reconnected to the failover Exchange serverB. This is perfect!
AkhaterSolutions Architect

Commented:
of course it explains it,

Your clients are connected to server B at all times (as a CAS server) however your mailboxes are up on server A (as a mailbox server)

when you shutdown serverA databases are moved from server A to server B (as mailbox servers) but clients are still connected to serverB (as CAS server) so, once the DB are online on ServerB (as mailbox server), connection is re-established
Network Administrator
Commented:
No, the Outlook clients where always connected to serverA, it was the primary Exchange server, way before ServerB was ever online.  I even verified my connection before I disconnected the cat-5 cable on ServerA.

FYI- I believe I found what I'm looking for, this link explains how to manually change which CAS server Outlook will connect to.

http://clintboessen.blogspot.com/2012/03/changing-rpcclientaccessserver-how.html
AkhaterSolutions Architect

Commented:
Honestly this link is exactly what i have been telling you.
ei00004Network Administrator

Author

Commented:
The link I found explained exactly what I was trying to do.

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