Any issues with increasing maximum mailbox size for Exchange 2010?

The boss of a company for whome I am responsible for their exchange server has a full mailbox. The current mailbox limit is 2Gb (pretty standard).

He's asked if I can bump his mailbox up to something around 10Gb in size. The exchange server is located on the same physical network as he is on 95% of the time.

Is there any "gotchas" I should know about before agreeing to bump his mailbox to 10Gb? What issues may we encounter if he actually fills his account to 10Gb?

Solution 1:

As long as you've got the disk space and backup capacity there's not really an issue. Exchange has been able to handle large mailboxes for a long time, and Exchange 2010 does a stellar job.

Outlook would be the only place where I'd have any cause for concern, and then only if the user is using an older version (pre-2007). Newer versions of Outlook aren't going to have problems with such a large mailbox (and older versions really won't, either, unless you're doing caching).

The only performance problems I've seen with Outlook and large mailboxes relate to large numbers of individual items in folders, but that's more of a count-of-items problem and not a size-of-items problem. The user shouldn't keep 20,000+ items in a single folder and expect it to perform well.

You might consider using the personal archives feature in Exchange 2010 if the user needs to keep a lot of old data around, but there's no reason you can't keep it in his mailbox, just as well.

Solution 2:

I'm going to add another consideration to Evan's answer. Users with large mailboxes lead to large databases. The larger the database, the longer the recovery time in the event of a disaster. That's something the boss should be made aware of. How many hours is it going to take to recover a database with 10GB mailboxes?

You could plan for high availability by keeping copies of the database on multiple servers. DAGs in Exchange 2010 totally rock! If the budget isn't available for that, consider moving into the cloud with hosted Exchange (make high availability somebody else's problem to worry about).

Solution 3:

If he gets to 10GB, he may start to notice performance issues compared to what he has today, but I have had MANY users with 6-8GB mailboxes with no problems. That said, Exchange 2010 has improved the compression algorithms with Outlook 2010, so they are even more efficient than Exchange 2007, and way better than 2003. The only caveat: Don't do it if you are not running gigabit Ethernet.

Solution 4:

To expand on my comment on Evan's answer, my experience is that mailboxes are never too large because of the messages, it's the attachments that cause them to grow. Limiting message size helps, but like most places, people here are always sending around powerpoint files and documents with pictures and it doesn't take too many 20MB files to add up to a GB. The problem is that email provides useful meta-data to many people: I sent this version of the file to these people on this date.

I haven't been terribly successful, but I'm always working on getting people to save their attachments, and then (or simply) delete them. In a couple of cases, I was able to train someone with a big mailbox to use MessageDetach to extract attached files, but that's about a 1% success rate.