The Outlook Personal Folders file (PST) had its day.  It was once the ultimate or perhaps only solution to reducing the cost of storing old emails within the Exchange server database.

Those days are largely gone.  Exchange servers can scale up to much larger database sizes than they could 10 years ago.  Disk and tape storage is cheap, and emails themselves are getting larger and larger.  And enterprise email archiving is efficient, cost effective, and even comes built in to the latest version of Exchange Server.

The benefits of the PST format are now close to nil, while all of the problems remain.  PST files are single-user access only, can’t be indexed or easily searched, are sensitive to corruption when they get larger or are being accessed over networks, and consume more space due to their general inefficiency.

But many organizations have a lot of archived emails still stored in PST files.  Moving to a new Exchange server doesn’t magically solve that problem.  The question is what should you do about all those PST files?

Do Nothing

The least effort, but also least effective solution is to simply do nothing.  Draw a line in the sand and leave all those PST archives as is, but begin archiving to a proper email archiving solution from this point forward.

A serious downside of this is that you can’t reclaim all that wasted disk space that the PSTs are using up.

Import to Exchange Server

The tools to import PST files into mailboxes have been around for a long time.  The upside of this option is that it gets the data back into a server database where it can then be archived off to a proper email archiving solution.

The downside is that you risk bloating your Exchange databases in the process.  You might also make a mess of people’s inboxes if the imports are not directed to the right mailbox folders.

Import to Email Archives

Any good enterprise email archiving solution includes tools for importing PST files into the archive database.  The advantage of this option is that the data goes straight into the archives, is indexed and searchable, and doesn’t negatively impact the Exchange Server in the process.

PST Discovery

In either of the import scenarios above one of the big challenges is discovering all of the PST files on the network and correctly matching them up to mailbox users.  This is relatively easy when PST files are in a standard location such as the user home drive, but more complicated if they are stored in shared folders on the network or on PCs.

Discovery is also problematic on PCs because they can be offline at any time of the day, unlike servers which tend to run 24×7.  Custom scripts and third party file system analysis tools can assist with this, but the process will still be labour intensive.

Unfortunately the end users are not likely to be too much help identifying and locating their own PST files, as it’s not a concept they all fully understand.

Preventing PSTs from Returning

At some stage when the PST import challenge has been met the administrator will want to implement measures to prevent PST files returning to the network.  Fortunately this is fairly simple with Group Policy settings for Outlook, and File Server Resource Manager tools for Windows servers that can be used to implement file screening.

Though there is some effort involved to do it right, ridding the network of PST files is beneficial in the long term.