There are two methods of issuing discards in Linux:
Online discard
- Discard operations happen in real time whenever blocks are transitioned from used to free.
- Enabled with the 'discard' mount option.
Periodic discard (Preferred Method)
- Batch discard operations discard all unused blocks on mounted filesystems at regular intervals.
- Enabled by systemd service or cron job. Consult your distribution’s documentation for setup instructions.
Note
- Your filesystem must support discard operations.
- You should use only one discard method at a time.