Hi Everyone, I want to design a solution for Exchange 2010 Active/Active datacenter model that have the following in environment. SiteA: SiteB: Direct Internet Direct Internet 2 HUBCAS (HUC1, HUC2) 2 HUBCAS (HUC3, HUC4) 2 Mailbox (MBX1, MBX2) 2 Mailbox (MBX3, MBX4) Have FSW Have Alternate FSW Active users 2000 Active users 1500 IRON Port 1 (MX1) IRON Port 2 (MX2) I want to have: Same namespace Internal and External OWA setting: Internal OWA setting: mail.domain.com mail.domain.com & Eternal:NULL Certificate name: Certificate name: mail.domain.com mail.domain.com CASArray Name: CASArray Name: siteACasAcarry.domain.com siteACasAcarry.domain.com WNLB: siteAnlb.domain.com WNLB: siteBnlb.domain.com Query: 1. For DAG design: Can i have single DAG (with DAC status DacOnly) between both Sites with all 4 mailbox server. **If my Site to Site connectivity goes down what will happen to SiateB database (stay mounted or will dismount) 2. Can I use the mail.domain.com as OWA url if any of Site goes down. I have read some articles but still in confuse. http://technet.microsoft.com/en-us/library/ee832790.aspx Thanks in advance NKumar

DataCenter Failover 4/2 + 1 = 3 You have atlease 3 votes , to have your DAG active. As you have DAC mode enabled - you have avoid split brain Syndrome. Where Databases won't come online until they get the confirmation of the other nodes Manual Process - Datacenter Failover As your have an Alternate File Share witness. you need to manually force the quorum to get the Secondary Datacenter online . If you face an outage in the primary Datacenter. Changing NAT . Is againg going to be a manual process. I Prefer If datacenter switchover happens. You got to change the NAT manually - and Force the alternate Share Witness manually to get the DAG members manually. These things cannot be automated. Only Server failovers are automated Satheshwaran Manoharan | Exchange 2003/2007/2010 | Blog:http://www.careexchange.in

thanks budy..its realy helpful Thanks in advance NKumar

Hi About DAG Design, you can refer to Database Availability Group Design Examples http://technet.microsoft.com/en-us/library/dd979781.aspx And for your second question, it can use, but the only problem is to resolve, you have to use NAT(Network Address Translation) to point to another site. Cheers Zi Feng

Hi Zi Feng, Thanks for reply, For my 2nd query, if my SiteA is completely down due to power failure in that case my Firewall, router and my internal server will be down, so in this case how NAT can be set. 2ndly If I use two alternate URL where my mail1 OWA url NAT with SiteA and mail2 OWA url NAT with SiteB. I want to use mail1 url as primary ulr so all users of both Site (A and B) to access mailbox and mail2 ulr as alternate url in such a way if mail1 is down users can access mailboxex via mail2. How we will configure OWA urls on both Site? Thanks in advance NKumar