Future of /Hosting Mode

Published Oct 13 2011 07:00 AM 14.3K Views

With the release of Exchange 2010 SP1, we introduced the /hosting mode switch – a feature which deploys Exchange using an Active Directory structure that affords complete separation between tenant organizations shared on the same underlying platform. /Hosting mode makes the need for a solution like Hosted Messaging and Collaboration largely redundant when hosting multi-tenant Exchange. /Hosting mode does not ship with any automation tools necessary for hosters to operate a service at scale, but it does address the requirements typical of a multi-tenant infrastructure (such as tenant organizations and service plans).

On one hand, /hosting mode solves many challenges inherent to offering this type of service. On the other hand, /hosting mode offers a reduced feature set as compared to the typical on-premises configuration. In the time since we released SP1 and /hosting mode, we have heard from customers and partners alike that many of these features are a fundamental requirement for doing business, and so to this end I announced that hosters would be supported when using the on-premises configuration from SP2 onwards (assuming their configuration meets certain design requirements). In addition, we also provided perspective on which is the right approach for hosters to take.

The purpose of this blog post is to explain the next step in the evolution of our thinking regarding /hosting mode. After hearing feedback about the importance of these features, we have concluded that the best approach to multi-tenant hosting on Exchange is to use the on-premises configuration as the basis for a hosting infrastructure. As such, no additional features will be added to /hosting mode, and it will not be carried forward into the next version of Exchange. Here are a few key facts you’ll need to know:

  • /hosting mode will be supported through the standard support lifecycle for Exchange 2010. It will still be available in SP2 and any future service packs or roll-ups. No additional functionality or features will be added to /hosting mode, however, and we don’t recommend using /hosting mode going forward due to its reduced feature set and the fact that it will add complexity to future upgrades.
  • Multi-tenant hosting on the next version of Exchange will be supported, in a similar fashion to the approach we will take with Exchange 2010 SP2.
  • 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 will publish guidelines for hosting a multitenant environment using the on-premises configuration. Microsoft will also publish a step-by-step process for upgrading from Exchange 2007 HMC or migrating from Exchange 2010 SP1 /hosting to Exchange 2010 SP2 using the on-premises configuration.
  • Hosting automation tools and control panel solutions will be provided by our hosting ISV partners. We are working closely with them to ensure their solutions meet our hosting guidelines (and will therefore be supported).

While this represents a change in direction, and will no doubt result in varying amounts of migration work on the part of hosters who have deployed /hosting mode, there is good news. This new approach means that hosters will be able to offer a wider set of hosted Exchange features to their customers. In addition, integrating Lync into a hosted service portfolio will be more streamlined and much simpler.

Looking at the data we presented at Worldwide Partner Conference, this opens up a sizeable market opportunity for hosters. Most customers looking to upgrade to Exchange 2010 cite the product’s advanced capabilities (such as Exchange UM – not available in /hosting mode) and a hosted UC service as a primary driver.

The obvious question you’re probably asking yourself is “what should I do now?” If you haven’t yet deployed Exchange 2010, our recommendation is to avoid /hosting mode and go directly to Exchange 2010 SP2 using the on-premises configuration. This will allow you to offer the features customers are looking for, and avoid a cross forest migration down the road.

If you’ve already deployed /hosting mode, you will continue to be fully supported through the standard support lifecycle of Exchange 2010, though you will continue to have a reduced set of features at your disposal. In addition, if you’re planning on hosting Lync and have deployed Exchange using /hosting mode, you will need to deploy Lync in a separate forest. You might consider switching to Exchange 2010 SP2 using the on-premises configuration.  If neither of these issues are considerations, stay the course until the next version of Exchange is available.

As I mentioned above, documentation for hosting as well as a step-by-step process for both scenarios will be forthcoming from my team in the coming months.

We appreciate the challenges involved with this decision are considerable, but we do believe this is the best, most flexible course of action available for our service provider partner community going forward. We will provide more information and details in the coming months, but wanted to be clear about this directional change as you make plans for your infrastructure today.

Kevin Allison
General Manager
Exchange Customer Experience

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Ok, bit frustrating but no doubt the right solution.

/Hosting was such as great idea though.

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Interessting news with much more possibilities (Hosting, Resource Domain, classic on Premise in one Exchange Org). But! You now have to deliver! As far as I know your internal "Dogfood" SP2 Version is stable and feature complete. You announced SP2 for the second half of 2011. There are only 2 and half Months left, so hurry up. And naturally you have to write a lot of technical white papers also. So, we are waiting Microsoft, where is the beef ...

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OK - good news I think.  But you really need to provide a solid date for SP2 so people can plan please?

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Being on the verge of implementing multi-tennant Exchange hosting I _really_ need a fixed date for SP2....

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SP2 is still on schedule for this calendar year. We realize that's not the specific date you want, but we really want to make sure we get SP2 thoroughly ready before we release. There are a lot of great features in SP2 covering a lot of different scenarios, and as soon as we have a date we can commit to 100%, we'll let you know.

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I know you said the documentation will be released in the "coming months", but is the documentation for migrating from a /hosting to SP2 going to be released with SP2, shortly after, or next year?

I look forward to having UM and being able to integrate Lync better!

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It will most likely be post SP2, but our goal is to get it out as soon as we can, we do understand the need for speed in this case.

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Great news ..!!

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A at least rough timeline would be great - we are in migration to Exchange 2010 with the /hosting switch.

Should we just go on or just wait 1 week, a few weeks ... and we would install instead the full fledged SP2 with the full Exchange 2010 funcationality?

That would be a big help also as information for the upper management.

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I fully understand and agree upon this new direction.

But what if a customer requires complete separation between tenant organizations (legal requirement)? This is not possible with a typical on-premises configuration.

I've read somewhere that Office 365 uses the multi-tenant version customized to fit the O365 infrastructure with Exchange UM & Lync 2010. Any future directions on this?


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@ Thomas - rough timeline is before the end of the year. As to whether you should stop or carry on, while I can't tell you what to do, I would suggest you look at what you can offer with a /hosting mode deployment, look at what an Enterprise deployment potentially offers you, and make your decision on that. If there are things in Enterprise you would like to have the ability to use that you know don't work in /Hosting (such as UM) then wait for Enterprise. Not ALL Enterprise features are going to work when configured for multi-tenancy, but a lot will, and a lot that don't exist in /Hosting.

@ Martijn - You are right that using Enterprise configured to make it work in a multi-tenant way is not the same as legal separation, though before deciding whether it will or won't meet 'legal separation' make sure you, and the people who will decide whether it is, or is not, have agreed on what the defintion is. Just advice I've learned the hard way over the years with the well-used phrase 'two factor auth'. If you truly need legal separation then you need multiple forests, multiple admins, as well as a ton of process and control.

As for O365, it uses a directory layout for Exchange which is basically the same as that in /hosting and has the same concept of tenants and separation, but there's a lot more to O365 than that. It's quite different from /hosting.

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With the two modes merging I have a question. MS's hosted exchange (I'm currenlty on the Friends and Family) has built in migration tools were you can:

Migrate organizations as an administrator

Merge multiple mailboxes into a single account as an end user

With the up and coming merging of feature sets will the migration tools become available to Enterprise (I.E. Non hosted) deployments?

As always love the blog, keep on posting,


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We don't currently have any plans to add those features to the Enterprise version of the product.

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Greg: The suck! ;) with the demise of MS's transporter suite (as far as I'm aware there's no plan for a 2010) versions there are no 2010 MS migration tools so you have to go 3rd party... it would be an amazing value add if they would make an appearance.

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You mentioned not all enterprise features are going to work when configured for multi tenancy....... What features won't?

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That will be explained clearly in the guidance we will be publishing. It's important to realize that some features may actually 'work', but wouldn't be supported in a multi-tenant configuration as they may potentially expose data from another tenant. In that case the feature would be unsupported and not recommended in a multi-tenant scenario.

The guidance will make very clear what is, and is not supported, as well as what is, and is not recommended.

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Awesome! Thanks Greg!

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Really frustrating! We implemented the SP1 /hosting mode for our new hostingsolution, only because Microsoft said we dont support you othervise. Multi tenant is only available with hosting mode, and if you go for the on premises solution you will not have any support from microsoft. And now you turn your back on hostingmode? And no upgrade ways? Create a new exchange forest? Again! This sucks.

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Microsoft put my company in a very bad situation, I deployed hosted exchange with /Hosting mode and I was about launching within few days. Now, all of our plans are shuffled because this decision.

I need to know if redeployed exchange with on-premises configuration using exchange SP1, and will deploy SP2 once Microsoft issued it. Will I find a support for my farm from Microsoft during the duration between working on-premises configuration and without SP2?

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@Peter - you are correct that we have changed our stance on supporting hosters who use enterprise. We're doing this to try and provide more features to hosters, rather than continue with a mode that limits features. Migration from /hosting to Enterprise will require a new forest deployment, that's correct.

The guidance we will provide will aim to make this as painless as possible.

@ Mohamed - If you deploy with SP1 it will not be supported I'm afraid. There are several key changes in SP2 that allow the features you need for a supported multi-tenant  configuration using the Enterprise product. If you have a control panel vendor that has an SP1 solution, they would be able to offer you support in the meantime, if you do not, I would recommend you wait for SP2. It isn't that far away.

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One additional comment - we are supporting /hosting for the full lifecycle of Exchange 2010. So if you were to stay on /hosting mode with 2010 that would be fully supported, you could then look to do the forest move for the next version of Exchange.

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Can you please let us know the best way to migrate from our /hosting SP1 configuration to the eventual SP2 Enterprise Multi Tenant Configuration?  What happens with the users that are online, do we have to do a manual migration?

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As mentioned above, documentation for a step-by-step process for that scenario will be published by the Exchange team in the coming months.

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This is crap - set up a new forest and migrate? We have just in the past two months deployed a very large /hosting mode cluster, worked around most of the problems and now have to start again.

There needs to be a better way than "start again and migrate".

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Studied day and nite for the /hosting thing .. spend whole nights in implementation.. ordered servers /hardware... not start learning again ...? or should i say msoft is not capable of integrating those new features or upgrades in the new version...


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when we are expecting the SP2? As mentioned SP2 will hold built in segregation like hosting. Do we expect true and complete segregation like the one we have in hosting mode plus all the missing feactures of hosting mode?

what is involve in upgrade from sp1 to sp2 for those who configured on-premise mode for hosting.? Microsoft was saying everyone that on-premise mode for hosting is not supported but time showed that all those who configured on-premise mode for hosting was right and even MS switched his path towards that implementation. Very Poor product planning from MS this time.

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@ JT - we understand it will be hard moving to a new forest, but we will be providing detailed instructions and scripts to help with that process should you choose that path. You can stay with /hosting for 2010 and move in the future though, if what you have is working and provides the features you need, maybe staying with it for now is the right course of action.

@ Qaiser - SP2 is later this year, and as previously mentioned, it does not provide a multi-tenant solution out of the box. If you have already deployed SP1 and managed to configure it to appear multi-tenant, you will need to either go with an approved control panel vendor solution, or convert your solution to follow the guidelines we will publish if you want to get support.

@ Jatin - many of the skills you learned will be useful no matter what version of Exchange you go with. In fact having a good understanding of service plans and the like would be very useful if you choose Enterprise and have to effectively create service plans from scratch. If you know what a service plan contains, you can script a bunch of setting that amounts to a service plan quite effectively.

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Hello friend

It really is bad news.

But tell me one thing, I have Exchange 2010 SP1 running 37 domains, as he is hosting.

I was thinking of migrating to Exchange Hosting version, but with this news it is not possible.

I know that managing Exchange 2010 SP1 with multiple domains is a huge headache, but my doubt is:

When you leave the SP2 I can just install the SP2 service pack?

Or will I have to redo all my environment?

Thank you friend.

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Hi Silvio, if you have SP1 Enterprise today, you should be able to add SP2 and then move to using ABP's for directory pretty easily. Don't migrate to /hosting, wait for SP2, then test, test, test to make sure an upgrade works for you with your configuration. Anyone who has somehow configured Exchange 2010 RTM or SP1 to appear multi-tenant needs to do the same - test it works for you, before installing it. Then plan on changing your configuration to follow the guidelines we will be publishing.

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I will wait and test, test ...

It was a pleasure talking with you and thank you for the excellent information.

Silvio Tavares


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this is great news . When is Exchange 2010 SP2 due to release

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This is another frustrating false start in the multitenant Exchange Server space. Our organization implemented the Hosted Exchange Framework with Exchange 2003 and pulled it after a year because it was completely half-baked and nobody at MSFT new who supported it. Now, within the span of a single service pack, MSFT changes it up again AND requires deployment to a new forest for migration between the two.

This is one area that has been handled quite poorly. As a Managed Services provider,  it is difficult to have confidence in Exchange Hosting given the track record.

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SP2 has been released :)


..waiting for whitepaper on /Hosting...

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Happy to see SP2 out as promised b4 DEC... Thanks Msoft.. now please release those white papers and plz dont make the transition lengthy... :) make it step by step and simple so we dont waste much time reading instead we take our customers to SP2 directly...Thanks Again Msoft

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Our guidance will be out very soon, don't worry, and @ Jatin specifically, the amount of time it takes to migrate or transition is going to be dependant on how complex the environment is. Most successful Exchange deployments and migrations have a heavy dose

of planning in them. Many of those that don't end up calling in for support.

The British army even have a phrase for it (though I have removed one of the 7 P's as this is a family show): Proper Planning and Preparation Prevents Poor Performance  -


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Thanks @Greg..!!!

i am still ok with scratching the exchange sp1 and installing sp2 from start.. but was wondering couple of things ..

1. went to download site its only 500Mb is it correct

2. any link or help which can give an idea about the installation .. specially on hosting side ... am not really concerned about migrations really but if i have to do new installation also then i just want to make sure about the proper planning and things needed... as you advised...

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The download is a full, SP2 slipstreamed build. So it is the full product, that's why it's 500 MB. You can use it for upgrades or fresh installs.

The upcoming blog post about hosting will (I hope) provide the answers you are looking for. The post and the associated guidance will be published in the very near future.

Get SP2 installed today in a lab, take a look at Address Book Policies, as you'll be needing those.

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hi Greg.. Thanks for the answers yesterday ... i was jusy checking the SP1 on SPLA website and its around 4+gb.. and now sp2 is only 550Mb ... how you guys did this .. are we missing something ... if according to you this can be used for full installation/ fresh install with hosting capabilities.. please advise...!!!

one more things this will still be covered under SPLA ..the same way...as the previous version were...?

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UM lang packs. One includes them, the other does not, they are available as standalone downloads.

No changes to licensing with SP2.

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Hello Greg

Because Exchange 2010 hosting mode was discontinued by Microsoft, it brought a huge headache for IT company here.

Talking with some friends we are moving to Exchange SP2 on a whole new environment, the Dell servers already arrived and are being implemented within, but by what I read this SP2 did not bring anything new to those who have to work with Exchange Hosting multiple domains with so, as we are a company with dozens of domains need to have the product working that way.

But the advantage of Exchange 2010 SP1 running at hosting is that each director of each domain manages your e-mail accounts and policies without having to go here for the Matrix understood.

But from what we saw here in the new installation of SP2, it installed the same way as always, via graphic and not with the command / hosting because it no longer exists, but so far everything seems to be normal as the Exchange until we can put the acceptable domains by EMC SP2, but this way those who have to manage all email accounts would be the same here and that is exactly what we do not understand.

If you have some stuff talking about where we have the option to create multiple domains in SP2 and how is the management of each domain in this new version would be very grateful.

Thank you again.

Silvio Tavares - Systems Analyst

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SP2 is out and here is a guide on creating and configuring multiple tenants for SP2:


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