Exchange 2010: The New Archiving Feature

There is a lot of buzz surrounding the new archiving feature in Exchange Server 2010. But where there is buzz there are always the unavoidable rumours and misunderstandings surrounding the new feature.

When you ask an Exchange administrator about archiving, most of them think of the archiving product as a tool that replaces messages and/or attachments with a shortcut often called a stub, and then takes the original item and stores it in the archive system.

This is a deeply-entrenched misunderstanding, and when Microsoft revealed that the Exchange 2010 archiving function does not take items away from Exchange store, people started to shout and exclaim, This is not a true archiving solution! I admit that at first I agreed with this outcry from the Exchange community, but the more I thought about it, the more I realised there are good reasons to keep items inside Exchange.

First, you must put yourself in the shoes of a regular user. He or she often has a mailbox quota enforced and when the user gets a warning message they typically move items away from Exchange and store them in a PST file. This seemingly innocent move causes a very big problem.

PST files, as their name implies, stands for Personal Store and should be stored locally on end users’ hard drives. The result? There is no longer any backup on those mail items, and even if you go the unsupported route and save the PST file on a file share somewhere, the backup software often has issues with doing backup of these files since Outlook has them open.

What about using special tricks, such as open file agents, you might ask? Unfortunately, the backup software will still experience difficulty in performing the backup of open files even with such tricks. Outlook also changes the archive bit on the PST file, which in turn triggers the backup software to perform a backup even if there is no change in the file from Outlook. This will cause the backup to run for an extensive length of time since there are typically many PST files scattered across numerous file shares.

Another roadblock administrators may face when storing PST files “over the network” is that networks are unreliable and do not always function properly. Even if the networks are working, users are prone to closing the lid on their laptops, causing the network link to close and the PST file to corrupt since it was not properly closed by Outlook.

This is also the main reason why PST files are not supported on file shares. The corrupt PST file is also notorious for engendering end users to call the help desk, and essentially forcing the administrator to initiate a restore of the hopefully backed up PST file. Other problems exist with PST files located on a share, including but not limited to that of slow network performance when open, and when closing Outlook.

The risk of taking data out of Exchange and storing it inside PST files is that you are moving corporate data from a safe environment located inside Exchange databases to an unsafe environment. Since PST files can easily be corrupted and/or lost, they are not a secure alternative to storing business-critical data.

By moving corporate data out of Exchange you may in essence be breaking laws regarding retention and compliance because the administrator no longer has control of email content. Let us not forget that corporate assets are in danger of being lost by moving data out of Exchange.

Other issues to consider include legal discovery and reducing the burden of searching and restoring mail data. When moving data from Exchange to PST files, you have the potential of losing all those things.

Other archiving solutions often solve all or many of the aforementioned problems by using the “stub” approach, and can provide some kind of search capability. The stub approach is something that most vendors claim to be a viable alternative, but keep in mind this also introduces problems since items are removed from Exchange and are no longer indexed and searchable from a native client, forcing you to utilise the vendor client. That process entails installing and maintaining another client, which can be complex both for the end user and for the administrator.

Most vendors also claim that you would reduce the amount of data in Exchange with the stub approach. That is often true, but in many cases you do not reduce the data as much as you expect since the stub is another item in the Exchange database with a couple of Kb in size. By replacing a 10Kb mail with a stub of 5 Kb, you only save 5Kb of data. This is something that you should consider if you import PST files to Exchange and then archive those imported items-- this will in fact increase mailbox size by a couple of Kb per item you import even if you later archive it.

Next page: The Exchange 2010 approach