What is volume autosize in Data ONTAP?
Applies to
ONTAP 9
Answer
What does volume autosize do?
- Volume autosize is a policy-based space-management feature in ONTAP that allows the volume to grow by an increment if the volume is nearly full
- The nearly full threshold is defined by the flag
wafl_reclaim_threshold
- When a write is sent to the node that is larger than available space, ONTAP will try to write as much as possible before failing the write with a
volume full
message- During the next check, the volume will grow by increments until it has reached the minimum free space threshold
- This means that autosize is best described as 'grow on use,' rather than 'grow on demand,' a distinction that should be remembered when planning thresholds and grow increments
- Note that volume autosize does not infinitely grow the volume.
- The volume will grow until it reaches the maximum autosize value and then no more space will be allocated
- The grow and grow_shrink modes work together with Snapshot autodelete to automatically reclaim space when a volume is about to become full; the volume parameter -space-mgmt-try-first controls the order in which these two space reclamation policies are attempted
Autosize Command Syntax
- Use the volume autosize command to edit settings
- View the configuration with the volume show command
Additional Information
- Volume autogrow (autosize) feature does not trigger at expected threshold
- How to use Snapshot Autodelete
- For Data ONTAP 7-Mode use the vol autosize command outlined in Data ONTAP® 8.2 Commands: Manual Page Reference for 7-Mode, Volume 1