Personal STorage files (PSTs) are created by Outlook when it generates archive files, when using legacy protocols (IMAP or POP), and whenever a user wants one (unless prohibited by an administrator). They sound like a good thing – they allow you to reduce the amount of information stored in your Exchange server (you DO have an Exchange server, don’t you?), they allow users to have more control over their own data, and they allow users to handle their own document retention.
Every single one of those is a bad thing. While a user advocate would indicate that giving users more control reduces the need for that control to happen at a corporate level, the truth is that in today’s litigious society and with the current Federal Rules of Evidence (that’s the USA version, there are similar laws/rules in many countries), a company needs to know what information a user has access to. This is truth regardless of whether the information is new, old, or somewhere in between.
Anything that is potentially discoverable, in the electronic sense of the word, needs to be defined and controlled. This is because anything that is potentially discoverable can be used against a company in court.
Written policies are the first line of defense for any company. However, they are just that – written policies. A company must also regularly educate its employees about information control and train them on how to be compliant to those written policies. Many companies now make it a termination level offense to violate those policies.
However, in fairness, policies can be difficult to follow. They can have many steps involved in their processes and when it comes right down to it – if it gets in the way of an end-user getting their job done, they’ll probably ignore the policy as much as possible.
PSTs make avoiding rules easy. Especially since storing PSTs on a network share is not supported, PSTs are often located on individual user workstations and are invisible to corporate governance and corporate policies. However, you can bet that if your company becomes involved in a legal battle and you allow PSTs – all of your PCs will be impounded for search! Note: just because you DO store your PSTs on a network share does not mean that it works for everyone or that it is supported. It’s definitely not supported!
PSTs are also hard to search. While there are a number of solutions for local search of PSTs (Windows Indexing Service, Google Desktop, Xobni, etc.), none of these provide a mechanism for doing enterprise level search (that is, searching for a term across all the PSTs in an enterprise).
PSTs are hard to backup. Many companies do not back up their user’s workstations. In fact, many companies will choose to re-image workstations whenever a problem occurs, instead of spending help-desk time attempting to figure out problems.
In Exchange Server 2010, Microsoft removed limits on the size of mailbox databases and re-architected mailbox databases to work better when they are larger – this was done to encourage companies to eliminate PSTs from their environment.
However, the solutions that Microsoft developed do not fit the needs of all companies and many companies may be several years away from migrating to Exchange Server 2010. That does not stop their need for PST management. In that case, the companies should look to either in-house development or third party solutions.
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Last reviewed on Aug 23, 2011
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