How to define your archiving policy for user mailboxes

You must decide on the different groups of users that you want to archive (Provisioning Groups) and the policies to use for each group for automatic mailbox archiving.

Archiving from mailboxes can be based on one of the following strategies:

Age: Enterprise Vault archives items automatically as soon as they reach the specified age.
Quota: archiving keeps a percentage of each user's Exchange mailbox storage limit free. (Archiving based on quota does not apply to Exchange public folders.)
Age and quota: Enterprise Vault performs age-based archiving first. If age-based archiving does not make the required percentage of mailbox storage limit free, quota-based archiving continues until the required percentage is reached.

Consider archiving based on age and quota when archiving by age only or quota only do not give the results you want. When archiving is based only on age, it may not archive enough items to keep some mailboxes within their quota. When archiving is based only on quota, some mailboxes may not come close to the Exchange mailbox storage limit. In this case, Enterprise Vault does not even archive older items.

You can set a minimum age limit so that recent items are not archived to meet the archiving criteria.

Additionally, it is possible to archive the largest items first, so you get the greatest benefit from archiving relatively few items. This option is particularly helpful if you use archiving based on quota, or on age and quota.

For example, you can use the following settings. With these settings, Enterprise Vault first archives items that are larger than 3 MB and older than 30 days. It then archives all items older than 60 days:

Never archive items younger than 30 days
Start with items larger than 3 MB
Archive items when they are older than 60 days

As another example, you can use the following settings. With these settings, Enterprise Vault first archives items larger than 1 MB. It then archives items until each mailbox has 10% of its storage limit free:

Never archive items younger than 30 days
Start with items larger than 1 MB
Archive items until mailbox available storage reaches 10%

Enterprise Vault obeys the minimum age limit even if the result is that the available storage percentage is not achieved.

For more detailed information about archiving based on quota or age and quota, see the Administrator's Guide.