When you activate a new proposed ILM policy, existing objects might be moved to new locations or new object copies might be created for existing objects, based on the placement instructions in any new or updated rules.
In the currently active ILM policy for this example, objects belonging to Tenant A are protected using 2+1 erasure coding at Data Center 1. In the new proposed ILM policy, objects belonging to Tenant A will be protected using 2+1 erasure coding at Data Centers 1, 2, and 3.
In the currently active ILM policy for this example, objects belonging other tenants are protected using two replicated copies in storage pools at Data Centers 1 and 2. In the new proposed ILM policy, objects belonging to other tenants will be protected using three replicated copies in storage pools at Data Centers 1, 2, and 3.
When the proposed ILM policy in this example is activated, the overall performance of this StorageGRID system will be temporarily affected. Higher than normal levels of grid resources will be required to create new erasure-coded fragments for Tenant A's existing objects and new replicated copies at Data Center 3 for other tenants' existing objects.
As a result of the ILM policy change, client read and write requests might temporarily experience higher than normal latencies. Latencies will return to normal levels after the placement instructions are fully implemented across the grid.
To avoid resource issues when activating an new ILM policy, you can use the Ingest Time advanced filter in any rule that might change the location of large numbers of existing objects. Set Ingest Time to be greater than or equal to the approximate time when the new policy will go into effect to ensure that existing objects are not moved unnecessarily.