ONTAP provides temperature-sensitive storage efficiency benefits by assessing how often your volume’s data is accessed and mapping that frequency to the degree of compression applied to that data. For cold data that is accessed infrequently, larger data blocks are compressed, and for hot data, which is accessed frequently and is overwritten more often, smaller data blocks are compressed, making the process more efficient.

Temperature-sensitive storage efficiency (TSSE) is introduced in ONTAP 9.8 and is enabled automatically on newly created thinly provisioned ETERNUS AX volumes. You can enable temperature-sensitive storage efficiency on existing ETERNUS AX volumes and on thinly provisioned ETERNUS HX DP volumes.

Introduction of "default" and "efficient" modes

Beginning with ONTAP 9.10.1, two volume-level storage efficiency modes are introduced for ETERNUS AX series only, default and efficient. The two modes provide a choice between file compression (default), which is the default mode when creating new ETERNUS AX volumes, or temperature-sensitive storage efficiency (efficient), which enables temperature-sensitive storage efficiency. With ONTAP 9.10.1, temperature-sensitive storage efficiency must be explicitly set to enable auto adaptive compression. However, other storage efficiency features like data-compaction, auto dedupe schedule, inline deduplication, cross volume inline deduplication, and cross volume background deduplication are enabled by default on ETERNUS AX platforms for both default and efficient modes.

Both storage efficiency modes (default and efficient) are supported on FabricPool-enabled aggregates and with all tiering policy types.

Temperature-sensitive storage efficiency enabled on ETERNUS AC series platforms

Temperature-sensitive storage efficiency is enabled by default on ETERNUS AC series platforms and when migrating volumes from a non-TSSE platform to a TSSE-enabled ETERNUS AC series platform using volume move or SnapMirror with the following releases installed on the destination:

ONTAP 9.12.1P4 and later
ONTAP 9.13.1 and later

For more information, see Storage efficiency behavior with volume move and SnapMirror operations.

For existing volumes, temperature-sensitive storage efficiency is not enabled automatically, however, you can modify the storage efficiency mode manually to change to efficient mode.

Once you change the storage efficiency mode to efficient you cannot change it back.

Improved storage efficiency with sequential packing of contiguous physical blocks

Beginning with ONTAP 9.13.1, temperature-sensitive storage efficiency adds sequential packing of contiguous physical blocks to further improve storage efficiency. Volumes that have temperature-sensitive storage efficiency enabled automatically have sequential packing enabled when you upgrade systems to ONTAP 9.13.1. After sequential packing is enabled, you must manually repack existing data.

Upgrade considerations

When upgrading to ONTAP 9.10.1 and later, existing volumes are assigned a storage efficiency mode based on the type of compression currently enabled on the volumes. During an upgrade, volumes with compression enabled are assigned the default mode, and volumes with temperature-sensitive storage efficiency enabled are assigned the efficient mode. If compression is not enabled, storage efficiency mode remains blank.