After a crazy few days at PEX, and lots of conversations with people, one of the questions that kept coming up was how can I design and host Microsoft Exchange Cloud in a hybrid cloud model.
Great Question!! This is a great use case for the hybrid cloud. One of the easiest answers is You could split up your exchange design however you see fit. Client Access Servers could be hosted on vCHS providing the public facing part of Exchange, with the backend Mailbox servers on Premise perhaps, or split across multiple clouds for DR? Anyone who knows exchange, will be thinking now of all the different possibilities you could have.
In my opinion Exchange is the best product to come from Microsoft. They have advanced it tremendously with every release, and with Exchange 2013 you have all the built in Disaster Recovery and Disaster Avoidance features that really make this the ultimate enterprise messaging system (Disclaimer: This is my opinion, I am sure lots of other people dislike Exchange, or find it annoying and cumbersome. Perhaps its just Outlook for Mac that people hate, I know I do).
Before we start thinking about how we could build such an environment, lets look at some of the Disaster Recovery features within Exchange 2013:
Microsoft says: http://technet.microsoft.com/en-us/library/dd876874(v=exchg.150).aspx
Exchange 2013 includes several new features and core changes that, when deployed and configured correctly, can provide native data protection that eliminates the need to make traditional backups of your data. Using the high availability features built into Exchange 2013 to minimize downtime and data loss in the event of a disaster can also reduce the total cost of ownership of the messaging system. By combining these features with other built-in features, such as Legal Hold, organizations can reduce or eliminate their dependency on traditional point-in-time backups and reduce the associated costs.
Cool! Built in HA and DR. WHAT!?! Why are you talking about using Microsofts inbuilt HA and DR?? I know you are asking… Well, most public clouds don’t offer site to site DR, even public clouds running vSphere currently don’t offer Site to Site DR. For example, any vCloud Provider runs vSphere as the hypervisor. This offers you host based HA to restart your applications and workloads in the event of a host failure, but not in the event of a datacenter failure.
Why not use SRM?
I can here people saying it now! Its been asked multiple times this week “Why not just use SRM for failover?”. If you think about the whole cloud model, none of the underlying infrastructure is “presented” to the consumer. How can you use SRM without having access to vCenters across multiple locations? Not possible right. This is why the inbuilt features of Exchange 2013 make it perfect for cloud deployments.
Leverage Exchange 2013 Diaster Recovery Features
This is what Microsoft says about Disaster Recovery in Exchange 2013:
Disaster recovery: In the event of a hardware or software failure, multiple database copies in a DAG enable high availability with fast failover and no data loss. This eliminates the end-user downtime and resulting lost productivity that’s a significant cost of recovering from a past point-in-time backup to disk or tape. DAGs can be extended to multiple sites and can provide resilience against datacenter failures.
Again this is a cool feature.
So how could we design such an environment? At a very high level I have provided a basic list of how I think it could be done.
- Provision multiple Client Access Servers
- Provision multiple DAG servers
- Provision multiple Mailbox Servers
Site 2 (Off prem Cloud)
- Provision multiple Client Access Servers
- Provision multiple DAG servers
- Provision multiple Mailbox Servers
Site 3 (On prem Datacenter)
- Provision multiple DAG servers
- Provision multiple Mailbox Servers
Wow! Sounds interesting… So what would this actually look like?
Now looking at the above diagram, its very high level. I am not an Exchange expert, so I guess there will be caviats to it. Latency will be a big consideration if you are replicating between three sites, so the links will be critical. However the purpose of this is to show how you have the potential to build Disaster Recovery solutions at a relatively low cost by using the hybrid cloud and in built application technology/features. Think how much it would cost to build out three data centers? Using this kind of design you can simply purchase compute and storage resources in locations that you need at a relative low cost compared to purchasing the physical infrastructure.
I hope this taster gives you some food for thought about how you could build a hybrid messaging solution. Of course, there is some other considerations to bear in mind like backups and restores, but even then Exchange 2013 has some great features to remove the need for traditional file level backups.
- Recovery of accidentally deleted items Historically, in a situation where a user deleted items that later needed to be recovered, it involved finding the backup media on which the data that needed to be recovered was stored, and then somehow obtaining the desired items and providing them to the user. With the new Recoverable Items folder in Exchange 2013 and the Hold Policy that can be applied to it, it’s possible to retain all deleted and modified data for a specified period of time, so recovery of these items is easier and faster. This reduces the burden on Exchange administrators and the IT help desk by enabling end users to recover accidentally deleted items themselves, thereby reducing the complexity and administrative costs associated with single item recovery.
- Long-term data storage Sometimes, backups also serve an archival purpose, and typically tape is used to preserve point-in-time snapshots of data for extended periods of time as governed by compliance requirements. The new archiving, multiple-mailbox search, and message retention features in Exchange 2013 provide a mechanism to efficiently preserve data in an end-user accessible manner for extended periods of time. This eliminates expensive restores from tape, and increases end-user productivity by enabling rich clients such as Microsoft Outlook and Microsoft Office Outlook Web App access to older data
- Point-in-time database snapshot If a past point-in-time copy of mailbox data is a requirement for your organization, Exchange provides the ability to create a lagged copy in a DAG environment. This can be useful in the rare event that there’s a logical corruption that replicates across the databases in the DAG, resulting in a need to return to a previous point in time. It may also be useful if an administrator accidentally deletes mailboxes or user data. Recovery from a lagged copy can be faster than restoring from a backup because lagged copies don’t require a time-consuming copy process from the backup server to the Exchange server.
The possibilities are endless in my opinion.
Thanks for reading.
Excellent info here, David!