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Use the Exchange dumpster for long-term data retention at your own risk

The Exchange dumpster has the potential to be used as a long-term retention tool, but using it that way may cause more problems than it solves. Here's why.

Microsoft has made incremental changes to the way the Exchange Server “dumpster” works, adding to the length of time data can be stored there. Now, some IT pros use the Exchange dumpster for long-term data retention, but that can lead to serious issues.

For those not familiar with the dumpster, it's the part of the Exchange message store that retains deleted messages for a designated period of time, allowing them to be recovered when the need arises.

In Exchange Server 2003, Exchange 2007 and Exchange 2010, the dumpster default retention windows vary, but the retention window is also configurable in every version. For example, in Exchange 2003, the default value is only seven days, but it’s 14 days in Exchange 2007. This increase is a reflection of the increased amount of processing power and storage available to the average Exchange administrator.

Exchange Server 2010 featured a fairly radical redesign of the dumpster system. It was reborn as a folder named Recoverable Items that is indexed and discoverable, and dumpster data stays within the attendant mailbox rather than in a folder. Items manually removed from the dumpster by an end user are moved into a Purges folder, which has its own administrator-set retention policy.

Repurposing the Exchange dumpster
Regardless of the version, most folks who run Exchange use the dumpster to recover items that were deleted by accident. However, in companies that have legal compliance obligations -- such as Sarbanes-Oxley -- the dumpster may also be used as an all-purpose perpetual retention system.

I asked a number of fellow Exchange experts, "Does it make sense to use the dumpster as a compliance tool by enabling perpetual retention?"

The answer was a resounding "No."

The problem with using the dumpster as an infinite storage basket is that it causes data stores to balloon. This drives up the cost of the storage necessary to hold the data stores themselves and it also makes backing up and restoring problematic. Turning the dumpster into a compliance mechanism may seem convenient in the short-term, but over the long haul it creates more problems than it could ever solve.

Most admins I polled agreed that the best long-term e-discovery solution is an actual archive product. The products most often recommended were Metalogix PAM and Symantec’s Enterprise Vault . Both tools allow the Exchange store to retain messages for a reasonable amount of time -- 120 days, or maybe 180 if you really need it -- and have the rest packed away separately.

Point-in-time backups of the whole system that can be stored offline also help. That said, those backups need to be taken across an interval shorter than the dumpster retention period to be useful for e-discovery.

In short, any attempts to support legal discovery and compliance should be done using a full product whose sole purpose is just that.

Serdar Yegulalp
has been writing about computers and IT for more than 15 years for a variety of publications, including,, InformationWeek and Windows magazine.

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