We recently started using Microsoft's Hosted Exchange offering with Outlook 2010, and are very happy with it. So far we have been able to easily migrate calendars and contacts from old PST files into Exchange without any problems.
The only data still in PST files is archived email. I'm concerned about the bandwidth implications of having users upload all of their archived messages. We have a 30-40 GB of stored messages for all users combined, with some users having PST files that are several GB in size. We have three sites with the following bandwidth specs:
- Main office (25 users) is 5 Mbps / 5 Mbps
- First branch (10 users) is 5 Mbps / 512 Kbps
- Second branch (5 users) is 512 Kbps / 512 Kbps
If all the users start copying their messages into their Exchange mailboxes at once, will this kill our inter-site performance? Is Outlook/Exchange smart enough to reduce bandwidth use when the network connection is saturated, or do I need to ensure that QoS is configured before starting this?
Looking further down the road, what happens when a user with a 5 GB mailbox moves to a new computer? Does the entire 5 GB need to be re-downloaded, or can the OST from the previous computer be used to accelerate the process?
Any insight would be appreciated.