I don't think the personal archive option in Exchange Server 2010 completely addresses the issue of long-term message storage. Using .pst files for storage is popular because the files are free -- and server storage space is definitely not cheap.
Current server hard disk space is more reasonably priced and Exchange Server has the processing power to manage large information stores. Therefore, Microsoft designed the personal archive to reside alongside the user's mailbox in the mailbox database. The problem is that this design decision may force you to rethink your mailbox quota strategy.
By default, a personal archive has no quota limitations, so users move messages there to avoid mailbox quotas. However, some organizations will impose quota limits on personal archives as well, which seems to nullify the very purpose of using them. In these cases, the organizations have set both quotas and retention limits on their users' mailboxes.
Organizations doing this don't generally impose retention limits on personal archives. This means that while users cannot collect large quantities of messages in their archive mailboxes, they're at least free to keep archived messages for as long as they want.
Note: You can set a quota on an archive mailbox using the following command:
Set-Mailbox –Identity "User1" –ArchiveQuota 1GB –ArchiveWarningQuota 900MB
The future of personal archiving
Microsoft's decision to include the personal archive within the mailbox database has drawn sharp criticism from the IT community. Because of this outcry, the company did a lot of work on the personal archive in Exchange 2010 SP1. The most notable change is that the personal archive is no longer hard-linked to a user's mailbox.
In Exchange 2010 SP1, you can host a user's mailbox in one database and his or her personal archive in another. It's even possible to host users' mailboxes on-premise while simultaneously outsourcing the personal archive to an Exchange Server that resides in the cloud.
Personal archives reside within the same database as the user's mailbox and cause database growth. This leads not only to server hard disk consumption but also to more resource-intensive backup and restore operations.
Separating the personal archive from user mailboxes in Exchange 2010 SP1 creates a good alternative to .pst files -- as long as organizations are willing to pay for the required enterprise client access license (CAL).
About the author: Brien M. Posey, MCSE, is a seven-time recipient of Microsoft's Most Valuable Professional (MVP) award for his work with Exchange Server, Windows Server, Internet Information Services (IIS), and File Systems and Storage. Brien has served as CIO for a nationwide chain of hospitals and was once responsible for the Department of Information Management at Fort Knox. As a freelance technical writer, Brien has written for Microsoft, TechTarget, CNET, ZDNet, MSD2D, Relevant Technologies and other technology companies. You can visit Brien's personal website at www.brienposey.com.
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