Exam 70-345 topic 2 question 9 discussion

Actual exam question from Microsoft's 70-345

Question #: 9
Topic #: 2

HOTSPOT -
You need to recommend how many database availability groups (DAGs) and how many namespaces must be added to the site resilience solution to meet the availability requirements.
How many namespaces and DAGs should you recommend adding? To answer, select the appropriate options in the answer area.
Each correct selection is worth one point.
NOTE:
Hot Area:

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Suggested Answer:

Box 1: Number of namespaces: Four

Box 2: Number of Dags: Two -
Depending on your architecture and infrastructure you have two choices:
These choices are tied to the DAG architecture.
✑ Deploy a unified namespace for the site resilient datacenter pair (unbound model).
✑ In an unbound model, you have a single DAG deployed across the datacenter pair.
✑ Deploy a dedicated namespace for each datacenter in the site resilient pair (bound model).
In a bound model, multiple namespaces are preferred, two per datacenter (primary and failback namespaces), to prevent clients trying to connect to the datacenter where they may have no connectivity.
As its name implies, in a bound model, users are associated (or bound) to a specific datacenter. In other words, there is preference to have the users operate out of one datacenter during normal operations and only have the users operate out of the second datacenter during failure events. There is also a possibility that users do not have equal connectivity to both datacenters. Typically, in a bound model, there are two DAGs deployed in the datacenter pair. Each DAG contains a set of mailbox databases for a particular datacenter; by controlling where the databases are mounted, you control connectivity.
From scenario:
The servers in the New York and London offices are members of a database availability group (DAG).
Fabrikam identifies the following high-availability requirements for the planned deployment:
Mailbox databases that contain mailboxes for the New York office users must only be activated on the servers in the London office manually.
All client access connections to the London and New York offices must use load-balanced namespaces. The load balancing mechanism must perform health checks.
References:
https://blogs.technet.microsoft.com/exchange/2015/10/06/namespace-planning-in-exchange-2016/

by Harry83 at Dec. 28, 2020, 12:43 a.m.

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Harry83

4 years, 6 months ago

Not sure about the answer. According to the preferred architecture we would go to the recommended unbound model. https://techcommunity.microsoft.com/t5/exchange-team-blog/the-exchange-2016-preferred-architecture/ba-p/604024 Therefore only one "single" namespace for the datacenter pair (NY + London). With the "single" namespace we have only one FQDN per "protocol" : > autodiscover.fabrikam.com > mail.fabrikam.com > imap.fabrikam.com (if deployed) > smtp.fabrikam.com (if deployed) As we are talking about namespace and not "name" or "FQDN", I would say "One" because we are in a single namespace scenario (this is the Exchange Team recommendation & it permit to follow the requirement to lower the number of namespace). About the DAG number, I think we can have only one DAG that span over the two sites. This is implicitly said inside the states because it talks about london copies that should not activate automatically for NY users. One DAG can achieve the need. Of course we canalso have two DAGs or more but it will be more expansive as I require more servers. So I will go with One + One.

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Harry83

4 years, 6 months ago

I reconsider my position about DAG number. It should be TWO because on an upcoming question we set up a Blocked DatabaseAutoActivationPolicy on London servers.As it is a server wide parameter, we certainly need to have two distinct DAGs that span on both datacenters. Finally Ill go with One + Two :-)

upvoted 1 times

Rasto02

4 years, 5 months ago

I would vote for One + One. -Bound/Unboud model discussion: https://techcommunity.microsoft.com/t5/exchange-team-blog/namespace-planning-in-exchange-2016/ba-p/604072 (for 'unbound' model it is typical to have single DAG, for the 'bound' one 2 DAGs) - moreover..'The servers in the New York and London offices are members of a database availability group (DAG). Each mailbox database in the New York and London offices has three copies' (during transition E2013->2016 in NY/London datacenters, the number of servers will keep the same (4) and there would not be possible to have 3 copies of a MBX databaese if 2 DAGs be deployed..)

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