Hi!
Here is a tip… well two tips.
A) If you have large exchange accounts - make sure you have increased the default limits of the new Exchange server to support the accounts you are moving. You might need to reboot for this to take effect (it did not seem to take effect straight away for me)
On Exchange 2007 - do the following …
Open Exchange Management Console, expand Server Configuration, click Mailbox and then right click Mailbox Database under the relevant Storage Group and click properties. Under limits - adjust the settings to suit your organization. These numbers are in KB (Kilobytes)
Just FYI:
1,000 KB = 1 MB
10,000 KB = 10 MB
100,000 KB = 100 MB
1,000,000 KB = 1,000 MB (1GB)
10,000,000 KB = 10,000 MB (10GB)
100,000,000 KB = 100,000 MB (100GB)
The default is 2 GB which is pretty low these days. Maybe not for a new Exchange deployment, but if you are doing a migration/upgrade - then you will probably need to update the numbers.
B) If you are going from Exchange 2003 to Exchange 2007 - do a migration on the same server (Exchange 2003 to Exchange 2003) to a different Storage Group / Mailbox Store. This will allow Exchange 2003 to rebuild the database which will help reduce any corrupted messages when you do the second move to Exchange 2007.
An example of this would be to do the following …
On Exchange 2003 - Open Exchange System Manager and then make sure you have the Administration Groups/Routing Groups Enabled/Shown (Right click the root of Exchange System Manager (ie, usually it is displayed as your company name)) and click properties. Click ‘Display routing groups’ and click OK. You should now see something called Administration Groups. Expand this.
You will then have your Server name and then your Storage groups. Under your storage groups (ie, First Storage Group), right click and click New and then Mailbox Storage. Name it as temp or something similar. Create it in a location which has enough storage. Id say a different physical hard drive to help increase performance. After it has been created - it may take up to 15 minutes or so for AD to replicate (you might get an error so just wait).
Once done and the above is mounted - in the original storage group, right click on a mailbox (or several) and click Exchange Tasks. A wizard will come up. Select move, and then select the current Exchange server and then specify the new storage group you had created above. Afterwards when all the accounts have been moved - you can then use Exchange 2007 to move the mail boxes to the new server.
Even if you think your Exchange server is clean - save yourself some headaches and do the above first.
Now for client desktop settings… If they are using Outlook to connect via Exchange mode - then you might not have to do anything at all. The Exchange settings are stored in AD - so when Outlook opens after the migration, it see’s there is a new server and will connect without user intervention. You might have some issues if you have a client installed, like ActiveSync of which you may need to reboot / make sure no Outlook tasks are in Task Manager.
Overall - Migrations from Exchange 2003 to 2007 is not that hard. Just make sure you put time into it to find out any possible issues before you go live and of course, make sure you have a known good backup of your Exchange data! Plan for a long time - id say 24 hours per 100 GB of email (transfers will take less time.. but better to be safe, case you need to manually transfer accounts or have issues). So - a normal weekend for up to 150GB of email or a long weekend (Easter for example) if you have up to 300GB of email. If you have more… well good luck and happy working of Christmas!