Maximum Retention Settings - Technical Concepts

Document created by user.oxriBaJeN4 Employee on Sep 10, 2015Last modified by user.oxriBaJeN4 Employee on Mar 27, 2017
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Maximum Retention settings are critical to the integrity of your Mimecast archive as they control the length of time that Mimecast will store your organization's archived data.

  • Maximum Retention settings are set in days, at the account level of your Mimecast service.
  • The length of time set on your account should match the time outlined in your agreement.

IMPORTANT - Validate your Maximum Retention setting:

Maximum Retention Validation has recently been introduced by Mimecast. Details about this new feature can be found in the Retention Validation article.

To eliminate human error and provide a high level of data assurance for you organization, the Maximum Retention setting must initially be validated by a suitable Administrator. Every time the Maximum Retention changes validation will be requested again. Read the Validate Maximum Retention article to learn more about this process and how to confirm your Maximum Retention:

The Impact of the Maximum Retention Setting


Mimecast stores your organization's data in storage segments which can be viewed in the Administration Console in the Administration | Archive | Storage Segments menu. Storage segments are allocated by date and email data is stored in the segment that matches the sent date of the email.


Depending on the profile of your organization's mail flow, these segments will either be allocated on a daily, weekly or monthly basis. The greater the volume of email your organization sends and receives the shorter the length of the segment.


The segment time period is defined by Mimecast, and is calculated to provide the optimal experience for your organization.


The Maximum Retention setting has a direct impact on your organization's storage segments. Once the end date of a storage segment has passed the age as defined in the Maximum Retention setting, the segment will expire and become eligible to be purged.


If a storage segment contains emails that have been placed on Legal Hold, that segment will still expire but the items that have the Legal Hold applied will remain available for administrative searches until the time period defined for the Legal Hold has passed.

VERY IMPORTANT - Mimecast will purge an expired segment after 90 days unless one or more active Legal Holds have been configured on your account. Consequently it is critical to your organization's contractual agreement with Mimecast that the Maximum Retention setting is accurately validated by a suitable Administrator.

How to Find Your Maximum Retention Setting


Maximum Retention settings are defined in the Administration Console. To view the setting for your account, login to the Administration Console and navigate to the Administration | Account | Account Settings menu. The setting is shown in the Maximum Retention (Days) field.




How Email Retention is Calculated


Email retention can be calculated in two ways and is originally set at the point Mimecast first processes the email:




  • By default the calculation is based on the Maximum Retention setting for your service. For example, an email received April 24 2015 with a Maximum Retention setting of 3653 days (10 years) would be retained until April 24 2025.




It is possible to retain email for less than your organization's Maximum Retention using either:


  • A combination of Metadata and Content Preservation policies based on specific senders and / or recipients.




  • A Content Examination policy which allows you to set the Metadata and Content preservation lifespan based on Administrator defined content in message components.


For example, the same email received April 24 2015 with a Maximum Retention setting of 3653 days (10 years) and subject to Metadata and Content Preservation policies defined to retain email for 365 days (1 year) would be retained until April 24 2016.


When using these policies, emails that do not match the specific sender and recipient values defined in the policy will be subject to the default Maximum Retention setting. Once an email has passed its expiry date it is no longer discoverable in the Mimecast archive.


Features that can impact message retention


There are a number of Mimecast features that can impact an email's retention after its original expiry date has been calculated. These include:


  • The specified item was not found. - this feature uses the Mimecast Synchronization Engine and Administrator defined policies to adjust the retention of an email based on its folder location within the Exchange mailbox.
  • Retention Adjustments - a Retention Adjustment allows you to modify the original expiry date for emails in your organization's Mimecast Archive.
  • Legal Hold - emails placed on legal hold are retained for at least the duration that the legal hold is active, even if this is longer than the email's original expiry date. The expiry date of an email on legal hold cannot be changed by the Granular Retention Folders or Retention Adjustments features.




What happens if my organization fails to confirm the Maximum Retention setting?


This may result in Mimecast retaining your data incorrectly. Mimecast Account Managers will from time to time contact customers who have failed to confirm their Maximum Retention setting.


What if no one within my organization is a member of a suitable Administrator Role?


Please contact our Support team to inform them that your organization requires a Super, Full or Partner Administrator account in order to validate the Maximum Retention of your account. Our Support team will respond with the appropriate procedure to follow.


What if the password for an account that has a suitable Administrator Role has been forgotten?


Please contact our Support team stating which account requires a password reset and what Administrator Role it has. Our Support team will respond with the appropriate procedure to follow.


Where can I see who has a suitable Administrator Role within my organization?


Under the Administration | Account | Roles menu in the Administration Console you will find your organization's Administrator Roles. By clicking the Role itself you will be able to see who the members of the Role are.


Will we have to go through this process every time there is a change to the Maximum Retention of our Mimecast account?


Yes. After the initial confirmation Mimecast will seek further confirmation of the Maximum Retention setting after each update of this value.


What if nobody within my organization knows what the Maximum Retention of our Mimecast account should be?


Please contact our Support team or your Mimecast Account Manager. They will assist you with your query.


What if the current Maximum Retention is incorrect?


Please contact our Support team or your Mimecast Account Manager immediately. They will ensure that the Maximum Retention gets updated after appropriate checks have been carried out.