What can impact snapshot size and cause snapshot spill
Applies to
- Data ONTAP operating in 7-Mode
- Clustered Data ONTAP 8
- ONTAP 9
- Snapshots
- Cloud Volume Ontap
Answer
- The more the active file system changes and the longer Snapshot copies remain, the more space the copies consume.
- This is due to the fact that WAFL never overwrites a data block.
- If a file is modified, updated blocks are written to a new location.
- If data gets deleted from the active file system, old snapshot copies that contain that data will still point to those blocks, thus, space will not get freed up.
- Therefore, snapshots can become larger and grow beyond their snap reserve, thus, spilling into AFS (Active File System).
- If this happens, the user can use one (or a combination) of the following options:
- Increase snap reserve (Increase volume's size or enable volume's autosize mode)
- Change the Snapshot retention rate
- Configure Snapshot autodelete
- Backup Snapshots to DR
Additional Information
- Snapshots; including SnapShot Issues and Solutions
- How does the Snapshot reserve work?
- How to view snapshots and determine the size of snapshots
- How to use Snapshot Autodelete
- Deleted snapshots rolling over to older snapshots
- Individual snapshot size doesn't match the DF output for that volume
- Snapshots size show 0KB in the command line and System Manager
- How to reduce snapshot reserve in ONTAP 9