Helping people with computers... one answer at a time.

Backing up a large number of machines over a network has a number of challenges. PST files are only one aspect of the issue.

I work with about 200 end users. Most are power users on WinXP, and most use Microsoft Outlook. Unfortunately, most do no clean up of their email, so their pst files are about 2Gig each.

What is a good way to backup all of these pst files? Burning to CD/DVD? Using thumb drives? Hosting their PST's on a dedicated file server? Getting them all huge external hard drives? Or should we simply copy and overwrite their pst once a week to a file server, so their email program isn't actually working from off the network everyday?

In the ideal world, we'd change user behavior to clean up their PSTs to make them more manageable, and we'd implement one or more of the backup alternatives you mentioned.

However we're dealing with the real world here, and need a real world solution.

One thing that concerns me is that there's typically a lot more to life than a PST. How are you backing up everything else?

To just answer the specific question you've asked, here's the 'real world' path I'd head down:

  • Copy the PSTs from their local machines to a network backup server nightly. Weekly is not often enough, in my opinion. If these folks use email to any serious degree losing a weeks worth of email on restore from backup is too high a cost.

  • Backup that file server nightly, probably to tape. If all the user files are placed on the server overnight and the server is used for nothing else, then the tape backup could actually run during the day.

Like I said, I think nightly backups are important, and I think preserving those backups to tape is also important. Once on tape you can decide how long you want to keep your backups: a week, a month, a year, or longer. That becomes a policy decision, not a technical one.

With that out of the way, I want to address what I fear is a bigger issue. Great, you've backed up their PSTs. What about everything else on their machines? Perhaps they have work documents that aren't part of email that would represent a catastrophic loss if a hard disk crashed.

In other words, backing up email is not enough.

I believe you need to look at the much bigger picture of how data of all sorts is managed in your environment and how it's being backed up. Or not. Pick a random user's machine and ask: if this machine and all the data on it disappeared, how much of a problem would that be? I'm guessing there's more than email that your users would care about.

"... backing up email is not enough."

The problem here is that there's no single magic answer in an environment such as you describe. For the single machine home user an external hard drive and a good backup program are enough. For your situation you probably want something more comprehensive for your 200+ users.

One thing you can count on, though: even with the best of intentions you cannot rely on all 200 of those users to backup themselves. In an ideal world, maybe, but here in the real world? It's just not gonna happen.


  • Run a backup program on every user's machine, and send their backups nightly to a backup server, then back that up to tape periodically. This is pretty much like the PST-only solution above except it handles all data, not just the PST.

  • Rather than running the backup program on every machine, use some form of administrative network access to run a backup program on the backup server that fetches the data from the 200 machines over your network. Then backup to tape.

  • Have a nightly process on each user's machine that simply copies their data to a central server. This could be as simple as copying the "My Documents" folder tree, but you must be careful and double check before making that assumption. This also assumes that the "system" portion of each machine has no data worth preserving and that systems are easily reinstalled/rebuilt except for user data.

Of course you could give everyone an external hard drive and a backup program and set them up to backup each machine individually. For a set of machines that large and with that many users, the issue here is that there's no auditability, and each user needs to at least be able to notice if the backup's not working.

I can't resist talking just a little about the ideal world as well. Perhaps some of it'll rub off and generate some ideas that might make sense in your situation.

Ideally we'd educate all users in the importance of keeping their PST's lean and mean. Perhaps we'd have them create "archive" PSTs which could be kept out on your network somewhere while keeping their active PSTs small, fast, and more importantly easier to back up.

You might mention potential data loss to your users since older versions of Outlook's file format break when the file exceeds 2 gigabytes in size. It's also not enough to be running a newer version of Outlook; it's the file format in use that matters and Outlook does not automatically upgrade the file format.

And no amount of backing up - by your users or by you - will recover the data lost due to exceeding that file size.

Article C3017 - May 9, 2007 « »

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Leo Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

Not what you needed?

Jon Beaudet
May 9, 2007 11:35 AM

You hit the nail on the head, even with the very small amount of info I gave you, very impressive!
The larger picture of entire backups is the main issue here.
Most users do store all their data on the network, not their local c:drive.
So really, their local machine only holds their pst file and maybe some internet favorites.
I do like the "network acces" for backups you speak of.
Would running a batch file on logoff/shutdown via Active Directory be a good or bad idea?
Basically copying their pst to a file server, and then tape backup of that.

March 28, 2008 7:28 AM

mr. leo
i am using microsoft outlook 2007. i have a huge 6 gb + .pst file. all mails are important to me. my bussiness is running on these mails. i can't afforde to delete them. my problem is i cann't copy my .pst file to another disk or burn one dvd. when i try to copy a message appears saying " file size is too big". there fore i cann't format my system. it is working very slow.
can u give me any solution. waiting for your early and constructive reply.
thanking you

Leo A. Notenboom
March 29, 2008 6:44 PM

Hash: SHA1

Break the PST up into smaller ones on your machine first,
and then backup the smaller ones.

For example, I create a PST for each year as my archive.
Works great and copies easily.


Version: GnuPG v1.4.7 (MingW32)


January 15, 2010 1:16 AM

Large number of pst files is not easy to backup. it is recommended to use pst backup software. This has potential to backup all the files with all the details. user can backup pst with ease via outlook pst backup software.

February 17, 2010 2:05 AM

DataMills has a backup solution that can backup both PST files and other user's data.

The backup is managed and treats the PST files incrementally. Another advantage is reports.

Seach for DataMills EdgeSafe.

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