Today’s article is a tidbit of information, but important to call out for larger scale DAG deployments.
Exchange 2010 always uses the active database in the DAG as the source for log shipping during normal replication. That means that if you have multiple passive copies in your DAG, Exchange ships transaction logs from the active copy to each passive copy, even if some of the copies are in the same site. There is no peer-to-peer log shipping between passive copies in a DAG.
|Simple four node DAG with three passive copies
In the example above we have a single DAG with the active database and one HA copy in DC1, and one DR copy and a lagged copy in DC2. Log shipping occurs from the active database to the three passive copies, traversing the WAN twice for the copies in DC2.
This can have quite an affect on a complex enterprise deployment with multiple DAGs and many remote passive copies, so keep that in mind for your designs.
Note: Log shipping is different than seeding. Seeding is a file copy of the database to another server. Once seeding completes log shipping is used to keep that copy up to date. It is possible to seed a database from a specific server, perhaps one in the same site. For more information see the “Selecting the Seeding Source” topic in http://technet.microsoft.com/en-us/library/dd335158.aspx.
Exchange 2010 Unified Messaging can be used to create a disaster information message for employees. Typically you will have a dedicated phone number for this purpose and will advertise this number to employees on a regular basis. When a disaster occurs a DR coordinator calls into Exchange UM and records a message for employees, giving them information and instructions. You may want to visit Talking About Disaster for information and ideas about what to include in your disaster information message.
This article explains how to create an auto attendant for this purpose and how to configure Exchange to allow greetings to be recorded using the telephone user interface (TUI). I assume that you already are using Exchange Unified Messaging and that it’s configured properly.
Let’s get started.
- Create a new enabled* Auto Attendant called “Disaster Announcement” with a Pilot Identifier for the disaster information extension.
- Open the properties of the new auto attendant. On the General tab, disable speech-enabled and directory enabled.
- Set the Business Hours Greeting and Business Hours Main Menu Prompt to use the C:\Program Files\Microsoft\Exchange Server\V14\UnifiedMessaging\prompts\en\Silence-250ms.wav file. This will set the prompts to silence. Alternatively, you may want to use a WAV file saying, “There are no disasters right now. Call back later” for the Main Menu prompt.
- Set the Times tab to Always Run.
- Clear all the options in the Features tab.
- Configure a new Key Mapping called “Announcement” that runs the “Disaster Announcement” auto attendant (itself) when the user presses no key (time-out). This will cause the auto attendant to loop. Alternatively, you can configure it to play the Silence-250ms.wav file, which will loop indefinitely until the caller gets bored of hearing nothing and hangs up.
- Clear all the options on the Dialing Restrictions tab and click OK to save the changes.
Then use the TUI to configure the auto attendant greeting when a disaster occurs. Read Enable Custom Prompt Recording Using the Telephone User Interface for instructions on how to do this.
* If you create the auto attendant as disabled you will run into an interesting problem where you cannot save the AA configuration changes because the AA references a disabled AA (itself).