Create ILM policy: Overview

Contributors netapp-madkat

When you create an ILM policy, you start by selecting and arranging the ILM rules. Then, you verify the behavior of your proposed policy by simulating it against previously ingested objects. When you are satisfied that the proposed policy is functioning as intended, you can activate it to create the active policy.

Caution An ILM policy that has been incorrectly configured can result in unrecoverable data loss. Before activating an ILM policy, carefully review the ILM policy and its ILM rules, and then simulate the ILM policy. Always confirm that the ILM policy will work as intended.

Considerations for creating an ILM policy

  • Use the system’s built-in policy, Baseline 2 Copies Policy, in test systems only. The Make 2 Copies rule in this policy uses the All Storage Nodes storage pool, which contains all sites. If your StorageGRID system has more than one site, two copies of an object might be placed on the same site.

  • When designing a new policy, consider all of the different types of objects that might be ingested into your grid. Make sure the policy includes rules to match and place these objects as required.

  • Keep the ILM policy as simple as possible. This avoids potentially dangerous situations where object data is not protected as intended when changes are made to the StorageGRID system over time.

  • Make sure that the rules in the policy are in the correct order. When the policy is activated, new and existing objects are evaluated by the rules in the order listed, starting at the top. For example, if the first rule in a policy matches an object, that rule will not be evaluated by any other rule.

  • The last rule in every ILM policy is the default ILM rule, which cannot use any filters. If an object has not been matched by another rule, the default rule controls where that object is placed and for how long it is retained.

  • Before activating a new policy, review any changes that the policy is making to the placement of existing objects. Changing an existing object’s location might result in temporary resource issues when the new placements are evaluated and implemented.