So migration of your email account could runs for hours or could require multiple days, depending on how much email you have to transfer. If possible, we will try to schedule the copy process overnight to minimize disruption during working hours.
We can further minimize the disruption of your mail service by planning which folders to copy, in which order, which I call the phased migration strategy. Supposing that you have 12Gbs of mail to move, then if we initiate a copy at the end of the day, it will run until we hit the upload limit. The next day we will restart the transfer and again it will run until the limit, and so we will repeat until all of your email has been transfered. However, since we don't know in what order your folders will be copied, and, because you should avoid making changes to mail folders while they are being copied, it is therefore safest to not access your email at all while the migration is running. However, if we choose the order in which to copy folders, then you can continuue to use your mail, just avoiding changing the folders that are currently being copied. There are a couple of folders, specificly, that you access routinely whenever you use your email, which are typically named INBOX and Sent. (and also Trash, which we normally don't copy at all, since it is just trash, though you may also copy it if you wish). So a good phased strategy is to first reduce your INBOX and Sent folders to a size that we can move in a single overnight, perhaps 3 Gbs. (If you are a person who accumulates many years of email in your inbox, then a good way to reduce your INBOX is to organize it into folders by date, which you might give names such as inbox.2014, inbox.2013, ...) Then we can migrate your INBOX and Sent folder overnight, so that your essential folders are in place and you can resume using email with your new server the next morning, while still having access to your other folders on your old email server. Then we can transfer the rest of your folders at a convenient time, with the minor inconvenience that you should refrain from making changes to your other folders until they are moved over.. Using this phased migration strategy, we can get you reconnected to your email as quickly as possible.