Example 6: Changing an ILM policy

You might need to create and activate a new ILM policy if your data protection needs change or you add new sites.

Before changing a policy, you must understand how changes in ILM placements can temporarily affect the overall performance of a StorageGRID system.

In this example, a new StorageGRID site has been added in an expansion and the active ILM policy needs to be revised to store data at the new site.

CAUTION:
The following ILM rules and policy are only examples. There are many ways to configure ILM rules. Before activating a new policy, simulate the proposed policy to confirm it will work as intended to protect content from loss.

How does changing an ILM policy affect performance

When you activate a new ILM policy, the performance of your StorageGRID system might be temporarily affected, especially if the placement instructions in the new policy require many existing objects to be moved to new locations.

CAUTION:
When you activate a new ILM policy, StorageGRID uses it to manage all objects, including existing objects and newly ingested objects. Before activating a new ILM policy, review any changes to the placement of existing replicated and erasure-coded objects. Changing an existing object's location might result in temporary resource issues when the new placements are evaluated and implemented.
The types of ILM policy changes that can temporarily affect StorageGRID performance include the following:
  • Applying a different Erasure Coding profile to existing erasure-coded objects.
    Note: StorageGRID considers each Erasure Coding profile to be unique and does not reuse erasure-coding fragments when a new profile is used.
  • Changing the type of copies required for existing objects; for example, converting a large percentage of replicated objects to erasure-coded objects.
  • Moving copies of existing objects to a completely different location; for example, moving a large number of objects to or from a Cloud Storage Pool or to or from a remote site.