Microsoft Exchange Servers And Backups – Part II

 While backing up your data seems to be a main focus in almost every technical book, and manual, many forget or neglect to actually do backups.  This is an unsafe practice as it can result in the loss of your data.  Let’s talk about Microsoft Exchange server and backups.

 Having backups for your Exchange Server can ultimately save you from a terrible catastrophe.  Imagine having your company loose all contacts and address books from the past 3 weeks – no imagine loosing them from the past 3 months.  Either situation is undesirable, and can be prevented by having good backups of your Exchange Server.

 Microsoft Exchange Server’s backups are considered to be either online or offline, so we will take a look at each in more detail.  Part I of this article discussed online backups, and therefore in this article we are going to take a look at Offline Backups.

 Offline Backups

 Microsoft Exchange servers rely on log files for all transactions.  After creating the log files, it puts them into memory and then into a database file.  These files are essentials to the offline backing up of a Microsoft Exchange Server.  By writing ahead to these log files, Exchange server provides fault tolerance for the Information Store so that if a problem occurs Exchange can reconstruct the database upon restarting by reading from the transaction log files.

 Occasionally the Information Store data may become corrupt, but don’t panic – all is not lost.  In this case Exchange Server will look at the transaction log files on the hard disk and will reconstruct the database from that.

 Circular logging is important to offline back ups as well.  Your Exchange Server will overwrite logs that have already been sent to the database with new files and thus prevent buildup and reduce required disk space.  Keep in mind however, that circular logging will only enable you to restore information that was logged up to the last Normal Backup and not to the last transaction that took place. 

 It is essential that an Exchange Server Administrator weigh the advantages and disadvantages of backups before deciding on a definite back up plan.  For example, circular logging looks like a great thing because of recycling old logs and reducing required space, however, the overwriting of logs also greatly reduces your chances of recovering all of your data. 

 It is important to note that Microsoft does not recommend the process of using offline backups because of potential data loss.  In most circumstances you should practice online backing up.  In the event that online backups are unavailable or don’t work, however, you should know about offline backups.

 By:  Tracey J. Rosenblath