Hi Mr EBE

Because you have 4 sites that have active users on all 4 sites I would do 4 DAG.

DAG 1 - Site 1 active , Site 2 passive

DAG 2 - Site 2 active , Site 1 passive

DAG 3 - Site 3 active , Site 4 passive

DAG 4 - Site 4 active , Site 3 passive

1 HLB per site is ok.

Hi

I don't think that 4Mb of available bandwidth will support replication for 4 DAGs but you should check it out with the role requirements calculator: http://gallery.technet.microsoft.com/Exchange-2013-Server-Role-f8a61780

There are no "CAS Arrays" in Exchange 2013 but you can load balance two or more servers running the CAS role or collocate this role on your mailbox servers.

By de-duplication do you mean single instance storage?  This doesn't have anything to do with mail transport, what you need to consider is bifurcation: http://blogs.technet.com/b/rischwen/archive/2013/03/13/exchange-2013-mail-flow-demystified-hopefully.aspx (towards the end)

Steve

• Proposed as answer by cara chenMicrosoft contingent staff, Moderator 9 hours 8 minutes ago

Hello,

Please can anyone indicate me some values for the network bandwidth requirements for the following case:

4 Sites, each connected with 20Mb MPLS. Actually there is one non MS Mail system in each site. the 20Mb are 80% used in busniness Hour.
Site 1 : 200 users
Site 2 : 400 users
Site 3 : 600 users
Site 4 : 800 users (the "central site" with SMTP gateway)

The migration plan is to move to a multi-site DAG with active-passive DB in respective site + one lagged passive of each site in the "central" site.

By my lecture, the designe would be :

- 1 DAG covering the 4 sites
- 1 CAS Array per site
- 1 HLB per CAS Array

Can you please indicate me :
- if my design understanding is correct.
- the required bandwidth per user (20-50 mails per day at most, but as Exchange doesn't do deduplication, one email with 5Mo attachement sent to say, 100 users, represent 500Mo (Not Mb) of transfert, isn't it?
- if exchange 2013 DAG DB copy replication can be configured to be restricted to Of-business hours (per DB). Most needed in the time of coexistence/migration, when replication Data will be hughe..

Well, I would like real life multi-site replication experiments advice.. please.. would be greatly appreciated.

Thank you a lot

CZ

• Edited by Mr EBE Monday, December 09, 2013 10:44 AM

Hello,

Since your per datacenter has an active user population, we recommend you deploy multiple DAGs to eliminate the WAN as a single point of failure.

If your CAS server and mailbox server are installed on the same server, you will not use software load balance.

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