The problems with PST files

 In Hardware, Storage

Most companies cannot give users unlimited email storage on their Exchange server (although many users will attempt to test this reality). To control the amount of data begin stored, administrators implement quotas on mailboxes. When users reach their quota, they have two options: They can delete some email (yeah, right), or move it off the Exchange server.

Outlook uses PST files to store email outside of an Exchange system. The program prompts users to auto-archive old email to PST files by default, but users can also manually create them. While this sounds like a simple fix, most IT support will tell you that PST files are a pain in the neck to manage and in some cases create more problems than they solve.

To make matters worse, desktops and laptops are not always protected by a backup process. For this reason, users are taught to put documents and files they want backed up in their “home” folder on a network file server, which, in theory, is backed up regularly. As a result, users often put their PST files in their home folder and open them in Outlook to use.

Server administrators (or backup administrators) are responsible for backing up these file servers. There are two types of backups: full backups, during which all files are backed up, and incremental backups for files that have changed since the last full backup.

Archive attribute of a file

SCREENSHOT: The archive attribute of a file is denoted by the letter A.

Most backup programs use what is called the “archive” attribute to determine if a file has been backed up before. When a file is created or modified, the file system turns on this attribute. When a full backup is run, the archive attribute is cleared. When an incremental backup is run, only files that have this archive attribute turned on are backed up. This makes incremental backups smaller and therefore faster than full backups, and enables them to be conducted during the week. Full backups, meanwhile, usually happen on the weekends when more time is available.

How is this a problem?

  1. Here’s a fun experiment to show file server administrators:
  2. Put a PST file in a folder on a file share (such as a home directory). Clear the archive attribute on the file. You can do this by opening the file properties, choosing advanced, and unchecking the “ready for archiving” box.
  3. Open the file in Outlook. Don’t expand the PST folder. Don’t add or remove anything to the PST file. Then close Outlook.
  4. Go back to the file server and check the PST file’s archive attribute. It will be turned on again.
  5. Repeat this process (you can just open Outlook now that the PST file is linked in Outlook) and you will see that each time the PST file will be marked for backup.

In this scenario, even though the PST file was not modified at all, it will be backed up each night with an incremental backup. Multiply this by hundreds or even thousands of users with multiple PST files each and you get thousands of files totaling several gigabytes or even terabytes of space.

You will have the same exact PST files on hundreds of backup tapes, resulting in unnecessary costs of the tapes, the rising cost to shuttle them back and forth for storage, and the time wasted backing up files that don’t need backing up.

Here are some other problems with PST files:

  • They aren’t accessible through Outlook Web App (OWA), Outlook’s web portal.
  • By default, they’re created on the local laptop or desktop and usually not backed up.
  • Their default location is: C:\username\AppData\Local\Microsoft\Outlook, which makes them easy to miss when you’re transferring your data from an old computer to a new one.
  • They corrupt easily.
  • Email scattered and stored on multiple computers in thousands of files makes eDiscovery efforts much more complicated, time consuming, and expensive.

Though PST files can be difficult to manage, there are solutions available to ease the process. An archiving application — Symantec’s Enterprise Vault, for example — can locate PST files throughout the network — on desktops, laptops, or on file servers. It can pull those PST files to the archiving server and archive that email into the individual user’s email archive. Often, shortcuts to the PST file can be created in the user’s Exchange mailbox in a separate folder with the PST file’s folder structure intact.

PST file in Microsoft Outlook

SCREENSHOT: Imported PST file in Outlook with folder structure intact

When the PST file is imported into a user’s archive, the user can then access that email from any company computer or through OWA. The user also doesn’t have to worry about losing the email in that PST file due to corruption or hard drive failure.

SHI’s archiving experts have tools that can show an organization the number of PST files scattered throughout their network, and can explain why a company would benefit from getting rid of PST files and putting that email into an arching application. Email me for more information.

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