One of the new capabilities of Exchange 2010 is its expanded mailbox capacity. Microsoft asserts that it is possible to store years of email safely in Exchange 2010 without concern for mailbox size.
That may be true, but there is a potential problem with this approach.
What happens when you have to upgrade Exchange sometime in the future? Take, for example, the recent upgrade from Exchange 2003 to Exchange 2007. With this upgrade you had to physically migrate all mailbox content to the new server. It was a very time-consuming process, even for the much smaller mailboxes common with Exchange 2003. What happens if the same type of upgrade is required in a future version of Exchange, and mailboxes are 10GB in size (or larger)? The impact on upgrade will be huge.
This is something to consider if you are planning to greatly expand average mailbox size with Exchange 2010.
... Bob Spurzem, with many thanks to Martin Tuip, Exchange MVP, who raised this issue

One Comment
Spot on Bob- I think people should think about an archiving before migration strategy to avoid these issues.
Plus, what about the size of the PST/OST on the actual desktop???
Can you imagine how long it’ll take to re-sync after a new PC or failure. Ages!
And then the performance- Outlook 2010 is supposed to improve performance with larger PST/OST’s but even still, I’d rather have a smaller footprint on my PC and access by fast search.
By keeping an archive, they never have to worry about migrating their data from exchange version to exchange version ever again.
What about you? What do you think?
Justin
With the migration from Exchange 2007 to Exchange 2010, the end user has continuous access to his mail while the migration (=upgrade) takes place. Should there be another massive database change, I expect that that would still be the answer: migrate data at your leisure while the user can still function.
Although this will take a long time, the theory is that it shouldn’t be particularly time-consuming for the sys admin.
So what am I missing here? Is the real problem in dealing with the inevitable errors that arise?
Elizabeth,
I agree with your position and yes, the problems that may arise will likely be caused by the amount of data and chance for error.
But having said that, archives are not imune from upgrades either.
So anyway you look at it, storing years of email is potentially risky, but what choice do we have?
Bob.
Justin,
Thank you for the reply and yes I agree with you. I have to say that your opinion favors your company approach (Mimecast), but that is ok.
I will say that the move to hosted email makes sense on many levels, and if a company is considering moving their on premise email to a cloud provider, then it makes perfect sense to also keep archiving for email in the cloud.
I always felt that email archiving, for optimal performance, should sit locally with the mail server. So if the mail server goes from on premise to cloud, the archiving should naturally follow.
Good Selling.
bob.