Shulou(Shulou.com)06/03 Report--

General enterprise users pay more attention to the highly available (fault-tolerant) solutions of the following three roles. There is generally no fault tolerance for UM (Unified messaging) roles and Edge Transport roles.

A:Mailbox (mailbox role)-DAG--- prevents database corruption

B:HUB (Hub Transport role)-NBL--- for multi-link redundancy and load balancing

C:CAS (client access role)-CAS Array--- prevents front-end failures from affecting email sending and receiving

Typical (exchange2010) High availability Topology

Prerequisites for Exchange DAG deployment:

1.OS:win2008 Enterprise / Data Center

Both 2.Exchange2010 Standard Edition (supporting 5 databases) and Enterprise Edition (supporting 100databases) support

3.DAG is an CCR enhancement

4.DAG service relies on failover clustering service and supports up to 16 replicas

5.DAG does not need to share storage when deployed, which greatly saves costs for small and medium-sized enterprises.

6. The service of configuring DAG requires two network cards

7. In the DAG architecture, a witness server is required, which can be a HUB or a member Server in the same domain.

Witness server requirements for DAG:

1. When the number of DAG members is even, the witness server is required to implement and maintain the arbitration. If the number is odd, the witness server is not required.

two。 The witness cannot be a member of DAG, and it is generally recommended that HUB or DC act as the witness.

3. The witness must be in the same AD forest as DAG

4. A witness server can act as a witness for multiple DA, but each DAG witness needs to have its own separate directory.

1.DNS support

Domain name system (DNS) must be running. In theory, the DNS server should accept dynamic updates. If the DNS server does not accept dynamic updates, you must create a DNS host (A) record for each exchange server. Otherwise, Exchange will not function properly.

Each mail server in DAG must be a member server in the same domain.

The name assigned to the DAG must be no more than 15 characters and be a valid, available, and unique computer name.

two。 Member software requirements

In addition to meeting the prerequisites for installing exchange2010, all members of DAG must also meet the operating system requirements. Because DAG uses windows failover clustering technology, they need the windows enterprise version.

3. Network demand

Each DAG uses one "MAPI network" and zero or more "replication networks".

4. Witness server requirements:

The Witness Server is a server external to DAG that enables you to implement and maintain arbitrations when the number of ADG members is even. When the number of members of a DAG is odd, the witness server is not used.

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