ZFS Snapshot Checker

Script to check zfs snapshot counts and age of oldest most recent snapshot. Specifically, this script iterates over a number of specified datasets, determines for each the age of the most recent snapshot (with a specified prefix), and then computes the maximum of those ages. This can be used to monitor zfs snapshotting and replication tools such as zrepl, sanoid/syncoid. In addition, the script determines the number of snapshots for each specified dataset, as well as the maximum of those numbers. This facilitates monitoring of proper snapshot pruning.

Examples

# Basic check
./checkSnapshots.sh -d tank/data

# Recursive with verbose output
./checkSnapshots.sh -d tank/data -r -v

# Provide limits (max 20 snapshots, max age 24h), resulting exit code 1, if limits are exceeded.
./checkSnapshots.sh -d tank/data -s 20 -m 24h

Options

• -d, --dataset <dataset>: Dataset to check (required; can be repeated for multiple)
• -p, --prefix <prefix>: Snapshot prefix (default: zrepl_)
• -f, --format <format>: Timestamp format (see below)
• -s, --max-snapshots <num>: Max snapshots per dataset
• -m, --max-age <duration>: Max age (e.g., 31s, 17m, 24h)
• -r, --recursive: Include sub-datasets
• -e, --exclude <dataset>: Exclude dataset (can be repeated for multiple)
• -v, --verbose: Show detailed table
• -n, --err-for-no-snapshots: Error if no snapshots found
• -h, --help: Show help message

Timestamp Formats (-f)

• zrepl-dense - 20060102_150405_000
• zrepl-human - 2006-01-02_15:04:05
• iso-8601 - 2006-01-02T15:04:05Z
• unix-seconds - Unix epoch
• sanoid - default sanoid format

Without this flag, ZFS creation time will be used.

License

MIT License - see LICENSE