Support for TRIM procedures

IBM Storage Scale Erasure Code Edition supports the TRIM feature to enable space reclamation.

Supported Configuration for TRIM

IBM Storage Scale Erasure Code Edition supports manual reclamation of free space for NVMe-based NSDs in 5.0.5.1 or later.

IBM Storage Scale Erasure Code Edition supports automatic reclamation of free space for NVMe-based NSDs in 5.1.5 or later.

For more information, see the topic Managing TRIM support for storage space reclamation in the IBM Storage Scale RAID: Administration and Programming Reference Guide.

Note: Before TRIM is enabled in production, the following requirements must be met:
  1. Disks that support TRIM need to meet the specified requirements. For more information, see Selecting physical disks for TRIM.
  2. System stability must be verified by running TRIM with a mixed file system workload (including read, write, and free up file space). In the test, the pdisk’s state must be kept in OK state to sustain recovery group and file system service. Only the tested firmware version can be applied in the production system.
  3. Automatic background reclaim is controlled with the config parameter backgroundSpaceReclaimThreshold, which may be set via the mmchconfig command. In Erasure Code Edition, this value may be set to 15 to enable the feature. Different backend storage devices respond to reclaim commands differently, and this may result in an impact on write performance. Before enabling Automatic Background Reclaim, it is recommended that you verify the performance of workloads that create and write to new files while deleting files at the same time. For more information, see the topic Automatic background TRIM in the IBM Storage Scale RAID: Administration and Programming Reference Guide.