MS Exchange 2010 – Maintenance Made Easy!
If you are running a Microsoft Exchange environment and have been for a while, you have probably at some point had to run an offline defrag of the Exchange database. This operation is particularly critical with database growth, or with frequent deletion and creation of mailboxes. It is also prescribed by Microsoft to fix certain issues that an Exchange database can experience. However, almost all Exchange databases require this maintenance at some point in their life cycle.
What is an Offline Defrag?
Essentially, an offline defrag creates a new database and copies all records and tables from the old database into the new file. It then deletes the original database file, renames the new database and then copies it into the original database’s location. One of the main reasons for doing this is to reclaim whitespace from the database file, as Exchange 2003 Standard has a hard limit of 16GB on the database. (Exchange 2010 has a 50GB default limit). Another reason is when the database becomes corrupt and needs to be repaired, an offline defrag is necessary in order to complete the repair (this is so you have a new database file that has not been repaired.
What are the downsides to Offline Defrag?
- Downtime - The Exchange databases need to be taken offline for this maintenance to be performed. In addition to this, the Exchange database can be corrupt during this operation leading to further problems (although very rare, this is a real concern for any offline maintenance).
- Time Consuming Process - Depending on the speed of your hardware, the amount of whitespace in your database and the size of your transaction logs, an offline defrag can process up to 4-7 GB per hour. That is upwards of 10 hours to defragment a 50GB database. It is also strongly recommended to backup the database immediately after running the offline defrag, which could be another several hours depending on your backup solution.
Exchange Mailbox Stores
One of the great things about the newest versions of Exchange is the ability to create another mailbox store. Exchange 2007 and 2010 actually have this ability. Once you create the new store, you can then move all of your mailboxes from the fragmented store into the new store. Now you have a defragmented mailbox store, and you didn’t even have to take your entire mail environment down to perform the maintenance! So if you are frequently creating and deleting mailboxes and tend to run a heavily fragmented Exchange database, you most likely will not have to bring your entire mail environment down to address it. Pretty cool!
Unfortunately, errors, corruption and other nastiness that can occur on your database will probably lead to an offline defrag regardless of Exchange version. But if you simply need to reclaim whitespace, it is now much easier. This is just one of many reasons to upgrade to the latest version of Microsoft Exchange.