ZFS Operations

Common ZFS operations.

Mounting Existing ZFS Pool

zpool import {POOL}
zpool status {POOL}
zpool scrub {POOL}
zfs mount -l -a

Note

A pool name does not need to be used to identify a ZFS container, it will be detected automatically. zpool import -a.
Search for the pool, then mount it, use -f if it wasn’t exported. Scrub.

Hint

Set mountpoint to immutable without the ZFS dataset mounted. This prevents writes when the dataset is not ready: chattr +i {MOUNTPOINT}

ZFS Filesystem Options

ZFS can be tweaked per dataset based on the data being used. ZFS only applies new settings on newly written data; changing options for pre-existing data requires export/re-import of that data to the dataset.

Enable text compression and disable atime for Maildir datasets.

zfs set atime=off {POOL}/{DATASET}
zfs set compression=lz4 {POOL}/{DATASET}

Enable high compression for backup datasets.

zfs set compression=gzip {POOL}/{DATASET}

Setup Monthly ZFS Scrub

Scrubbing verifies all blocks can be read, and marks then bad if not. This is done while the filesystem is online, but may slightly impact performance.

0750 root root /root/bin/scrub-zpool-monthly

#!/bin/bash
#
# Scrubs zpool monthly.
/sbin/zpool scrub {POOL}

Add to root crontab to run monthly.

@weekly /root/bin/scrub-zpool-monthly

Reference