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

When we use the Exchange system, we all want a reliable and available mail system every day. For many companies, mail systems are part of our business continuity plan, and site recovery should be taken into account when designing mail service deployments. Basically, many site recovery solutions involve deployment in a second data center.

Here are some official preliminary plans:

Ultimately, the overall design of the DAG, including the number of members of the DAG and the number of mailbox database replicas, will depend on each organization's recovery Service level Agreement (SLA) that includes various failure scenarios. During the planning phase, the architect and administrator of the solution will determine the deployment requirements, especially the site recovery requirements. They determine the location to use and the required recovery SLA goals. SLA will identify two specific elements that should be the basis for designing high availability and site recovery solutions: recovery time goals and recovery point goals. Both values are measured in minutes. The recovery time target refers to the time required to restore the service. The recovery point goal refers to the degree to which the data is old and new after the recovery operation is completed. SLA can also be defined as reverting to a full service after the problem in the primary data center has been resolved.

The architects and administrators of the solution will also determine which group of users need site recovery protection and determine whether the multi-site solution is an active / passive or active / active configuration. In an active / passive configuration, there are usually no users residing in the standby data center. In an active / active configuration, users reside in two locations at the same time, and in this solution, a certain percentage of the total number of databases is in the preferred active location in the second data center. When the services of users in one data center fail, those users are activated in another data center.

Building an appropriate SLA usually requires consideration of the following basic issues:

> what level of service is required after the failure of the primary data center? > do users need data services or just mail services? > what is the extent to which data are urgently needed? > how many users must be supported? > how do users access their own data? > what is the standby data center activation SLA? > how to move the service back to the master data center? > are resources dedicated to site recovery solutions?

By answering these questions, we can design a mail solution to build a general framework for site recovery design. The core requirement for recovery from a site failure is to create a solution to put the necessary mail data into an alternate data center that hosts alternate mail services.

In this series of blog posts, we use the establishment of cross-site DAG to achieve remote disaster recovery of the mail system, that is, suppose that the data center of our company's headquarters also has a data center in Beijing and Shanghai, which is used for data backup and disaster recovery of Exchange mail system.

When there is a disaster in the Beijing data center, start the disaster recovery server in Shanghai manually so as to achieve remote disaster recovery. RTO is less than 1 hour and RPO is less than 15 minutes.

The following table shows the network information of my test environment, all virtual machines:

Server name operating system IP address gateway DNS role BJAD01windows server 2012 R210.1.110.1.1.1010.1.1.1 Beijing domain control 01BJEX01windows server 2012 R210.1.210.1.1.1010.1.1.1 Beijing Exchange01BJEX02windows server 2012 R210.1.1.1010.1.1.1 Beijing Exchange02SHAD01windows server 2012 R2172.16.1.1172.16.1.1010.1.1.1 Shanghai domain control 01SHEX01windows server 2012 R2172.16.1.2172.16.1.10172.16.1.1 Shanghai Exchange01SHEX02windows server 2012 R2172.16.1.3172.16.1.10172.16.1.1 Shanghai Exchange02Routerwindows server 2012 R210.1.10 172.16.1.10\ Router

The environment topology information is as follows:

The environment is ready for this, and in the next article we'll create a configuration router!

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