This script automates the management of a MergerFS pool backed by SnapRAID. It moves files from a cache drive to a backing pool when they are older than a specified number of days or when the cache usage exceeds a set threshold. This helps optimize your storage by managing space effectively, leveraging MergerFS for combining drives and SnapRAID for parity-based redundancy.
In setups where MergerFS combines multiple drives into a single storage pool and SnapRAID is used for redundancy, this script:
- Moves older or less-accessed files from a faster cache drive to slower storage (backing pool).
- Helps ensure that the cache drive stays below a certain usage threshold, preventing it from filling up.
- Works well for media libraries or archival systems, where frequently accessed files remain on fast storage and older files are shifted to larger, slower drives.
- MergerFS: A union filesystem that combines multiple directories into one pool.
- SnapRAID: A backup solution that protects data with parity across multiple drives.
- Cache Management: Moves files older than a specified number of days (
N=5by default) from the cache to the backing pool. - Usage Monitoring: If cache usage exceeds 85% (default), it moves the least recently accessed files to free up space.
- Logging: Logs all operations, including file movements and script activity, to
/var/log/expire_cache.log.
- Cache Directory: A faster drive where frequently accessed files are stored. Defined as:
CACHE="/srv/disks/cache01"