Exchange 2010 Archiving: Dumpster Revealed

Exchange operates with a hidden deleted items folder referred to as the "dumpster." In Exchange 2007, end users can manually purge email in the dumpster, thereby bypassing an organization's legal hold. This was a major legal risk.

Exchange 2010 introduces a new and substantially improved dumpster that fixes this design flaw, and offers additional benefits.

End users can use the dumpster to restore single emails that were deleted by mistake. Here is how it works: When an email is first deleted it moves to the Deleted Item folder. It remains there until the Deleted Item folder is emptied. Next, the deleted email moves into the dumpster where it is held according to a retention policy set by the administrator. Normally the dumpster retention period is set for 30 days, allowing users to change their mind and restore deleted email within that period.

The dumpster retention period can be set for longer periods or an unlimited time, and this is the important benefit to the organization. Organizations that require retention of email for regulatory compliance, for example, can use a dumpster retention period of n years as prescribed by the law. Organizations facing legal discovery can set the dumpster retention to an unlimited period, in effect putting email deletion on hold until the legal case is resolved.

Dumpster retention periods are set on a per-mailbox basis. Thus, if a legal case requires some of a user's email to be retained indefinitely, for example, then all that user's email is retained indefinitely.

Finally, it should be noted that the dumpster has an important role in the new backup strategy adopted from Exchange 2010 onwards. Because Exchange databases are so large, traditional backups and restores have become impractical. Thus, the approach to backup with Exchange is now:

  • Keep one or more live copies of an Exchange database in case the main one gets damaged.
  • Keep copies of emails around for some extended period elsewhere; e.g., in the archive or in the dumpster, so that users can restore a damaged or deleted email if they need to.

... Bob Spurzem

In addition to his role as Ferris analyst, Bob is director of product marketing at Permabit, which offers a grid–based disk storage system.

One Comment

  1. Posted April 13, 2010 at 7:11 AM | Permalink

    Interesting article Bob…

    You state “keep one or more live copies …. in case one gets damaged” – I’d debate whether this is a viable strategy to _replace_ backups.

    I’d readily agree that it can augment a backup strategy and help mitigate against failure/corruption, but it is more about “resilience” or live data protection than backup. It is basically single point in time (just a moment ago) copy (albeit there may be multiple copies of that ‘just a moment’ ago copy).

    I know the MSFT hype around this, but for me backup is more about _multiple_ “point in time” copies that allow me to restore from a particular previous instance and provide a contingency against any of my backup instances also being corrupt – defence in depth.

    .. Ken

  2. Nate Fitzgerald
    Posted April 13, 2010 at 8:38 AM | Permalink

    I am wondering how this is different than the deleted item retention in previous version of Exchange (http://www.msexchange.org/tutorials/MF022.html)?

  3. bspurzem
    Posted April 13, 2010 at 6:51 PM | Permalink

    Ken,

    Your view is correct. DAGs provide multiple copies of the data, but all at the same point in time. If you wish to keep multiple point in time copies, then use Windows VSS enabled backups using one of the many 3rd-party backup products.

    the additional benefit is that the VSS backups can be copied to tape and store safely offsite.

    A DG group can also be hosted in a DR site, but it requires the infrastructure, server etc. More costly than just sending backup tapes to a fire proof vault.

    I hope this helps.
    Bob.

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