Today’s businesses, large and small, depend on their email systems for a significant majority of their communication needs. Email has developed from a rudimentary, inaccessible technology used only by the tech-savvy to its current role as a rapid, reliable communications tool for just about everyone. 

Along the way, as user needs and data storage have evolved – remember when 1 Mb of storage was a big deal? – the use of email systems has increased well beyond their original scope of sending and receiving short messages. Today’s email systems provide calendaring, group collaboration, task management, workflow and, ever-increasingly, file and data storage. Users now store many years worth of email and attachments, and refer back to them on a frequent basis for important historical information.

This increasing document retention, along with the ever-increasing size of attachments, has caused email systems to dramatically increase in size and therefore demand higher technical capacity and management. Meanwhile, the email content itself has increased in value – often being sensitive, proprietary or even mission-critical in nature. It is essential that today’s business protects its email investment and associated systems with document retention and archiving policies. An effective policy will balance system needs for security & stability with user needs that include rapid access.

Over the years of working with our clients, Seitel Systems has developed a set of best practices for dealing with these complex needs. Outlined below are our recommendations for retention and archiving under Microsoft’s Exchange Server.

Group Policy Templates

Regardless of whether Outlook Auto Archive is used to manage mailboxes, the Outlook Group Policy Template should be used to centrally control settings (including whether or not archiving is allowed). Configuration information is available below.

Outlook 2007: Outlk12.adm

Outlook 2003: Outlk11.adm

Exchange 2000 Environments:

Exchange 2000 is limited in the amount of available storage to 16 GB (17 GB for short term repairs). As a result, SSL recommends that these organizations implement mailbox management policies as follows:

1. Mailbox Size Limits: to 500 MB or smaller depending on the overall size of the organization. Smaller organizations can have larger mailbox limits. This should be managed through mailbox quotas enforced by Exchange Server. As users approach their assigned quota they’ll receive warning messages to that effect. Once they reach the quota they’ll be restricted from sending and receiving emails.

2. Outlook Email Auto Archive should be configured for all users to run with the following settings:

  • Turn On Auto Archive: Yes
  • Run AutoArchive every days: 7
  • Prompt before AutoArchive runs: No
  • Delete Expired Items: No
  • Archive or delete old items: No (note: this is a setting relevant to email retention policies and expiration dates, not the deleted items folder)
  • Show archive folder in folder list: Yes
  • Clean out items older than: Never
  • Permanently delete old items: No (note: this is a setting relevant to email retention policies and expiration dates, not the deleted items folder)

3. Archive folders should be stored in the following locations:

  • Workstation users should archive to a pst file located on the network. This runs the risk of file corruption as MSFT recommends against using a network share for email auto archiving but alternative solutions (such as archiving locally) entail greater risk of data loss due to disk or backup issues.Search the Microsoft support site for kb/297019 to find the supporting article.
  • Laptop users should archive to a pst file located on their local hard drive. A manual process will be required to copy these psts to the network on a regular basis (minimum weekly) to ensure that they are backed up. SSL recommends placing a recurring appointment on the user’s calendar.
  • A manual process will be required for all users to ensure that individual pst files do not exceed 2 GB in size. The frequency of this process will depend on the rate of email sending & receiving, but should be checked on at least an annual basis. SSL recommends placing a recurring appointment on the user’s calendar.

Exchange 2003 Environments:

Exchange 2003 is limited in the amount of available storage to 75 GB. This is likely more storage space than will be consumed by the average small business, but for those businesses that approach this limit SSL recommends one of the following solutions:

  • Upgrade to Exchange Server 2007 with its near-unlimited storage space. This is the likely solution for businesses on older hardware or simply wanting to take advantage of the features of 2007.
  • Add in a second mailbox store on the existing Exchange Server and migrate mailboxes to balance the storage load. This solution assumes available disk space and remaining useful life of the server hardware.

Due to the large available storage space and the inherent complexities of archive files SSL does not recommend implementing mailbox size limits or email auto-archiving policies except for laptop (mobile) users. Prudent user management of their mailboxes is encouraged through deletion of non-essential emails especially those with large attachments that do not need to be archived. The Outlook Group Policy Template should be used to prevent users from enabling Auto Archive on their mailbox.

Mobile users with large mailboxes will experience significant performance degradation when operating outside of the office LAN. Cached exchange mode or offline storage files are not recommended as they are both limited to 2 GB file sizes, plus their required synchronization time can be painful when done over a WAN connection (broadband or otherwise). For mobile users SSL recommends the following:

  1. Outlook should be configured to use RPC over HTTPS to allow secure access to the Exchange Server whenever the laptop is connected to the internet
  2. To keep performance at an acceptable level it is recommended that mobile users need to keep their mailboxes below 500 MB in size. This could be managed through mailbox quotas enforced by Exchange Server.
  3. Auto Archive should be enabled for mobile users to run quietly every 7 days and archive information to a pst file located on their local hard drive. A manual process will be required to copy these psts to the network on a regular basis (minimum weekly) to ensure that they are backed up. SSL recommends placing a recurring appointment on the user’s calendar.
  4. A manual process will be required for mobile users to ensure that individual pst files do not exceed 2 GB in size. The frequency of this process will depend on the rate of email sending & receiving, but should be checked on at least an annual basis. SSL recommends placing a recurring appointment on the user’s calendar.

Exchange 2007 Environments:

Exchange 2007 offers near unlimited storage limited only by the available hard drive space. As a result, SSL does not recommend implementing mailbox size limits or email auto-archiving policies except for laptop (mobile) users. Prudent user management of their mailboxes is encouraged through deletion of non-essential emails especially those with large attachments that do not need to be archived. The Outlook Group Policy Template should be used to prevent users from enabling Auto Archive on their mailbox.

Mobile users with large mailboxes will experience significant performance degradation when operating outside of the office LAN. Cached exchange mode or offline storage files are not recommended as they are both limited to 2 GB file sizes, plus their required synchronization time can be painful when done over a WAN connection (broadband or otherwise). For mobile users SSL recommends the following:

  1. Outlook should be configured to use RPC over HTTPS to allow secure access to the Exchange Server whenever the laptop is connected to the internet
  2. To keep performance at an acceptable level it is recommended that mobile users need to keep their mailboxes below 500 MB in size. This could be managed through mailbox quotas enforced by Exchange Server.
  3. Auto Archive should be enabled for mobile users to run quietly every 7 days and archive information to a pst file located on their local hard drive. A manual process will be required to copy these psts to the network on a regular basis (minimum weekly) to ensure that they are backed up. SSL recommends placing a recurring appointment on the user’s calendar.
  4. A manual process will be required for mobile users to ensure that individual pst files do not exceed 2 GB in size. The frequency of this process will depend on the rate of email sending & receiving, but should be checked on at least an annual basis. SSL recommends placing a recurring appointment on the user’s calendar.

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