Posted on:
June 4th, 2009
You should always have one mailbox database per storage group. If possible only one database per storage volume. The real benefit with this is if you are using VSS to back things up. Since VSS backs up entire volumes and then restore a particular volume without affecting another database.
If you are a real keener there is added benefit gained from keeping transaction logs on a separate volume. Having the Transaction logs are REALLY beneficial when you have more then 200 users.
When you are sizing your Exchange 2007 database you should really keep Recovery Time Objective (RTO) in mind. The reason for this is they should be able to be restored in a reasonable timeframe.
A good way of finding this out is TESTING!!! Find out how long your particular hardware takes to restore and backup. Every company will be different. For example. Say you have a small organization with 10 Users. Each of those users has 20GB Mail boxes. It would take longer to restore their database then a company that has 100 users with 10MB mailboxes.
There are several ways to divide mailboxes. The three most used options are:
Function – For example you might want to have different databases for Executives, Support Staff and Temps. A backup like this can help you prioritize the restore based on the function of the user within the company. For example temps might not need access as fast as say a support staff or Admin staff member.
Geography – You for example could put the West Coast in one storage container and the East Coast in another. If your company is located in a single building you might use “Old Section” and “New Section”.
Size and Backup Resources – You could split up the mailbox via Alphabetical order. A –> M and N –> Z. Say there are two user name Wilma and Waldo. Both of those users have VERY large inboxes. The N –> Z side might be much larger then A –> Z.
In this situation you might want to setup mail boxes based on size. A –> F and then user G –> Z. This might make the two data sources a bit more equal in size.
Remember to also take into account that these mailboxes will grow.
Mailbox Server Role Storage Requirements Calculator – Is a tool Microsoft has made available for free download. This program will help you figure out how to create separate storage units.