How does Temperature Sensitive Storage Efficiency affect SnapMirror?
Applies to
- SnapMirror
- Temperature Sensitive Storage Efficiency (TSSE)
Answer
- Temperature Sensitive Storage Efficiency is a method of compressing data based on data "temperature", or how often the data is used
- "Cold" data, or data that is not used often, is recompressed with a higher compression ratio for increased storage efficiency
Additional Information
Default Configurations in ONTAP
- TSSE is enabled for new volumes on AFF platforms running ONTAP 9.8 through ONTAP 9.9.1
- In ONTAP 9.10.1 and later, TSSE is no longer default for new volumes on AFF platforms and must be enabled explicitly on volume creation
- In ONTAP 9.10.1 and later, TSSE is enabled when
storage-efficiency-mode
on a volume is set toefficient
- TSSE is available for existing volumes on AFF platforms running ONTAP 9.10.1 and later
SnapMirror Interactions
- TSSE settings are inherited by SnapMirror destination volumes and the SnapMirror relationship will maintain deduplication and compression savings from the source volume with some exceptions (see the next section)
- No steps are needed to enable TSSE on SnapMirror destination volumes if supported by the ONTAP release and platform
- When replicating TSSE volumes to a ONTAP 9.6 or earlier destination, SnapMirror may fail with "
Invalid data operation(Replication engine error)
" or "Failed to start transfer. (Operation not supported)
" see BUG 1384963 for more details and fixed releases. This issue does not occur with ONTAP 9.7 or later destinations - If replicating from a TSSE volume to a destination in ONTAP 9.7 or earlier, compression savings will be lost over the network. SnapMirror will continue to maintain deduplication savings
- TSSE is not compatible with FabricPool until ONTAP 9.10.1. If replicating from a TSSE SnapMirror source volume to a FabricPool SnapMirror destination running a release earlier than ONTAP 9.10.1, compressed blocks are decompressed at the destination before being tiered by FabricPool
SnapMirror Destination Compression Savings
- TSSE requires contiguous Block Numbers to write data with compression successfully on a SnapMiror destination
- In cases where contiguous Block Numbers are not available, data may be written to SnapMirror destination volumes uncompressed or with reduced compression savings
- The typical scenarios where this occurs are:
- The destination aggregate is low on space. Maintaining ample free space on the destination aggregate can avoid losing compression savings with TSSE
- The destination aggregate is aged, meaning the aggregate and volumes within the aggregate have existed for a long period of time, resulting in fewer contiguous Block Numbers
Notes:
Even if the current environment does not meet the scenarios mentioned above, it cannot guarantee that the SnapMirror destination volume will maintain 100% of the compression savings from the source volume, TSSE will handle it automatically based on the real situation.