Unlimited Exchange Mailbox

i was pinged a few times asking why dont we support unlimited Exchange Mailbox where as lots of providers do.

I took the question to our Product team and here is what they shared with me, which i thought to extend to my friends here...

1. The primary reason for not having an unlimited mailbox size is the possibility of runaway mailbox growth. There are several scenarios, such as a Denial of Service attack, an auto-reply rule storm, a runaway automated process, or some other unforeseen event that can generate hundreds of thousands, or even millions, of email addresses to a single mailbox (or group of mailboxes), having it grow to astronomical proportions (100’s of gigabytes) in a very short time. We have seen this happen multiple times that we come in to help clean up. A runaway email box (or boxes) can quickly and easily expand to consume all of the available storage and resources of the mailbox server, and severely cripple availability for all other users of the system. (This impacts ALL customers on the hosted environment)

2. Secondarily, if we allow unlimited mailbox growth and the customer is charged for storage, this can result in an unexpectedly large bill.

3. Some providers who claim to offer “unlimited” mailbox size are actually offering an “arbitrary maximum” mailbox size. If you dig into their SLAs they state that there is a “functional limit”, which they do not define, and they also state that mailboxes should not be used as archives, which implies that if/when users reach this undefined functional limit, older items are the ones that get deleted/purged. So, none of our competitors actually offer unlimited mailboxes, just undefined, arbitrary mailbox limits.

4. As an Exchange mailbox gets larger, it becomes more and more difficult for a user to manage and use. This issue applies regardless of server configurations or resources – it is a matter of the complexity of having the Outlook client manage multiple gigabytes of mailbox storage and the corresponding tens or hundreds of thousands of individual messages.