Active Active Site Resilience

Not open for further replies.


I have two datacenter.Someof my users will be on Datacenter 1 and some of them on Datacenter 2. Each active directory site will have 2 mbx2 hub and two cas.It will be fully redundant.

But i want to use same namespace for these two datacenter.

In datacenter 1

WNLB Name :

owa,outlookanywhere and autodiscover url external and internal urls :

rpcclient access array : and points VIP

-------------------------All external mail traffic comes through datacenter 1 ..


If ı configure datacenter 2 external and internal url as and wnlb as and create another rpcclientaccessarray , will this configuration work?

I mean;

1 ) When datacenter 2 user receives mail from internet, this message will arrive datacenter 1 cas array, and will this array automatically redirect this message?

2 ) When datacenter 2 user connect to from external, he will go to dc1 again, and will this cas server or this car array redirect owa traffic to another site (dc2)

3 )Whena datacenter 2 user connects through outlook anywhere , he will come to the dc1 too.will this traffic redirected to the dc2?

4 )If i use active active datacenter model with same namespace like above , while i'm configuring datacenter 2 windows nlb for client access servers, should i choose same virtual ip name with datacenter 1? if that's right, then dc2 users will connect internally dc1 vip? or rpcclientaccessarray attribute on databases will control this?

Could someone explain these please?


Brian Day MCITP

Generally speaking I wouldn't suggest what you're trying to design and in some cases it just won't work. The recommendation is to have a namespace unique to each regional datacenter.

1. I'm going to assume your MX records point to Datacenter 1 (DC1 from now on). Is that correct or are there multiple MX records? If mail is delivered to DC1 for a user who's mailbox database is active in DC2, then hub transport servers in DC1 will route the message to the appropriate mailbox server in DC2. I would suggest reading the Internal Message Routing page to learn how internal mail is router to the most appropriate mailbox server in 2010.

2. Without some kind of global-load balancer you're generally looking at one of two scenarios here. Either the user will be told to use a different URL based on the ExternalURL values of the CAS servers in DC2, or you can configure it so the CAS servers in DC1 will proxy the request to CAS servesr in DC2. I would suggest reading the Understanding Proxying and Redirection in Exchange 2010 SP1 page to learn how proxying and redirectioncan work in 2010.

3. OLA traffic will hit CAS servers in DC1 and then cross-DC RPC traffic will happen if necessary for users to access mailboxes in DC2. Read the link in answer #2.

4. The RpcClientAccessServer attribute on Mailbox Databases determine what RPC endpoint Outlook connects to for MAPI/RPC connections. It would be more beneficial to have a CAS Array in each datacenter so clients use the CAS Array closest to the mailbox server their database is normally active on.

Microsoft Premier Field Engineer, Exchange
MCSA 2000/2003, CCNA
MCITP: Enterprise Messaging Administrator 2010
Former Microsoft MVP, Exchange Server
My posts are provided "AS IS" with no guarantees, no warranties, and they confer no rights.


thanks brian.
you confirmed all the sections.

But what will not work in such scenario?


Quote: “what will not work in such scenario?”

DAC mode won"t work if you build two members DAG across sites by using exchange 2010 RTM. You must use exchange 2010 SP1

ActiveSync will fail when database switchover or failover to different site, if the mobile device can"t process the HTTP 451 error correctly

Upgrading Exchange ActiveSync to Exchange 2010

If you have windows XP as client OS, and you also use one certificate for all CAS servers, please aware about the client limitation on the Certificate Principal Name


“Client Limitations” section in Understanding Digital Certificates and SSL

“Client Access Server Infrastructure” section in Designing a Site Resilient Exchange 2010 Solution (Part 3)

Not open for further replies.
Thread starter Similar threads Forum Replies Date
M Active/Active user distribution site resiliency Exchange Server Administration 2
F SMTP Relay to Remote Active Directory Site Exchange Server Administration 4
P Automate Outlook Start - No Active Explorer Object Found Using Outlook 10
S Active Directory Management Tools for Administrators New Articles 0
G Problems with Active Directory Rights Management Services (AD RMS) in Outlook 2013 Exchange Server Administration 0
Diane Poremsky Import Images into the Active Directory New Articles 0
S How to send an OUTLOOK task to a contact out of my active directory? Using Outlook 2
E Outlook rule only active certain times of day Using Outlook 6
R HELP!!! Email template with active excel spreadsheet Using Outlook 1
C active/passive broadband connections to maintain various IT services Exchange Server Administration 2
R Went from outlook 2003 to 2010 - can't retrieve active for contacts Using Outlook 0
J Setup mail for Exchange 2010 through Active Directory on Server 2008 R2 Standard Exchange Server Administration 3
W active sync Using Outlook 2
T Copied Contact Does Not Update With Active Directory Information Changes Immediately. How Do I Force Update? Using Outlook 1
E Using with Active Sync, Outlook become unresponsive Using Outlook 5
B Re: Exchange OOF / EWS Problem - The user and the mailbox are in different Active Directory sites Exchange Server Administration 0
M 'Send link by E-mail' doesn't provide active link.__ Using Outlook 1
J When a database move from active host in a DAG, user are prompted for credentials Exchange Server Administration 8
D Using Inbox as 'Active' tray, with both incoming and 'sent' mail, with senders and receivers displayed. Using Outlook 1
U Outlook 2010 Ignore Conversation Feature, list of Active Ignored Using Outlook 1
D how to give perrmission on calender to user in ACTIVE DIRECTORY Using Outlook 0
J OWA not working when active database moved Exchange Server Administration 3
S Web Links are not active when using Outlook Web Access 2007 Using Outlook 1
P How can I convert an Outlook 2010 folder to a .pdf with active links like I could in Outlook 2007? Using Outlook 3
T The Microsoft Exchange Active Directory Topology service on server localhost can't be contacted via Exchange Server Administration 2
P Will 'ldap modify' command work on some Active Directory fields? Using Outlook 2
S Active Passive DAG seperate DNS namespace Exchange Server Administration 7
E Event ID 9514 - Two objects in Active Directory have the same proxy address Exchange Server Administration 3
K publish exchange active sync behind TMG Exchange Server Administration 4
S Active Sync Device ID Using Outlook 2
C Active Directory error applying Exchange 2010 SP1 Exchange Server Administration 4
E Transfer calendar from a .pst to a user's active exchange account? Using Outlook 7
M Active Manager operation failed to mount DB Error Id: 50A399C7, ErrorId: BF128831 Exchange Server Administration 10
P Ex2010 active sync Exchange Server Administration 4
R Hi, Is Outlook 2010 compatible thru active sync with Windows Mobile 6.1 Professional. Using Outlook 4
O Exchange 2010 Service Pack 1 Active Directory Schema Exchange Server Administration 1
F Active Sync proxying not works in a Exchange 2010/2007 Coexistence Exchange Server Administration 1
K An Active Manager operation fail Exchange Server Administration 6
A No Word e Outlook 2010 não funciona o rolamento de página (scroll active) com mouse. Como corrigir Using Outlook 1
T Active Directory domain 'FECR' has an unrecognized Exchange signature. Current DomainPrep version: 1 Exchange Server Administration 2
M DAG Active/Active Exchange Server Administration 2
S Exchange 2010 - Active Sync issue - Samsung Galaxy S Exchange Server Administration 2
A CAS Proxying with Active Sync when migrate from Exchange 2007 to 2010 Exchange Server Administration 1
B DAG with active passive database configuration Exchange Server Administration 13
S Outlook reply window default tabs have changed from message being active, to now File being active. Using Outlook 1
P Send button is missing and account is active, can receive but can not send. Email removed for priva Using Outlook 1
V Restoring calender files that were deleted by Active sync Using Outlook 1
M Exchange 2010 Active Sync Device Recovery Password is not VISIBLE in OWA Exchange Server Administration 4
F Messages stuck in queue as active Exchange Server Administration 1
P Exchange 2010 SP1 and HTC Desire Active-Sync Exchange Server Administration 5
Similar threads