A few months ago we published a great article series from Paul Roman on implementing Exchange 2010 hosting. Paul provided two solutions, Exchange 2010 Hosting Part 1 - The Hard Way and Exchange 2010 Hosting Part 2 - The Easy Way. The "easy way" discussed using the /hosting installation parameter introduced in Exchange 2010 SP1. As explained in those articles /hosting comes with various limitations, but is easy to implement and is the method supported by Microsoft.
Unless you have been living on the moon, you will certainly know how much Microsoft has been pushing hosting. Thus changes and more development in this area are to be expected. Significant changes will indeed be introduced as from Exchange 2010 SP2, planned for final release later this year. These changes are important for 2 reasons:
- SP2 introduces new features targeting hosting environments.
- SP2 marks a departure in Microsoft's hosting support strategy.
I will not discuss the new features being introduced in SP2, check the links at the end for more on that. However let me just quickly mention Address Book Policies ABPs. This feature will tackle one of the most important requirements in hosting environments, that of separate Address Books for different tenants. In his article series, Paul discussed how this is done today. SP2 ABPs will allow you to manage address book segmentation directly from the Exchange Management Console and Shell interfaces.
What we said so far does not yet answer why you should think twice before installing /hosting. The reason for that is the change in support strategy. Microsoft will be dropping support for the SP1 /hosting in the long term. This was announced in the MS Exchange Team blog post, Future of /Hosting Mode. To put it bluntly, quoting from the blog, "no additional features will be added to /hosting mode, and it will not be carried forward into the next version of Exchange".
So now the puzzle is coming together. Exchange 2010 SP2 will improve the ability for on-premise installations to support hosted multitenant configurations. This is meant to eliminate the need for having a special mode unique to hosting environments. I can certainly see that the new strategy makes a lot of sense. We were moving in the direction where on-premise Exchange installations would have a very different feature set from that of /hosting installations. /Hosting was creating a different type of Exchange configuration, equating in additional cost in terms of support and development.
For those who rushed for a /hosting deployment this will certainly be bad news. For sure you don't expect a feature to be killed just after one service pack release! It is true that /hosting will continue to be supported for the entire Exchange 2010 life span. However beyond that, /hosting will be gone for good. Moving away from /hosting won't be fun either, "Migrating from Exchange 2010 /hosting mode to the on-premises configuration of Exchange (2010 or future versions) will require deployment into a separate forest." Microsoft promised to publish detailed documentation on how to perform such a migration.
This announcement will certainly discourage any further investment in /hosting from third party add-on vendors. For sure ISVs will be reluctant to develop any tools for an environment that will be gone as from the next Exchange release.
Final Tips
I certainly agree with the new strategy Microsoft is adopting with the introduction of Exchange SP2. Exchange is already very complex. Creating a new Exchange flavour with a significantly different feature set would have certainly been difficult and costly to maintain. On the other hand I understand the pain of those who already embraced /hosting. The Redmondonians could have saved the Exchange community some trouble with a little more foresight.
References
Exchange 2010 Hosting Part 1 - The Hard Way
Exchange 2010 Hosting Part 2 - The Easy Way
Announcing Exchange 2010 Service Pack 2
Future of /Hosting Mode