ZFS
How to use ZFS:
Background
There are three levels to understand
- zpools are a JBOD of one or more vdevs
- vdevs are groups of drives, likely in raidz (or raidz2, raidz3) or mirror.
- datasets are filesystems stored on a zpool, similar to partitions
- zvol is a virtual block device on a zpool without a filesystem
Usage
# Create a zpool with a mirror vdev. zpool create -f -o ashift=12 -o compression=lz4 $zpool_name mirror \ ata-diskA \ ata-diskB # Create a dataset. zfs create -o encryption=aes-256-gcm -o keyformat=passphrase $zpool_name/$dataset_name
- Notes
- You should always use the id under
/dev/disk/by-id/- E.g.
/dev/disk/by-id/ata-diskA
- E.g.
Alerts
First setup postfix to send emails.
Then setup ZED notifications
Automatic Scrubs
By default, ZFS on Ubuntu will automatically scrub every month
Automatic Snapshots
See sanoid
zfs list -t snapshot
Pros and Cons
VS Snapraid + btrfs + mergerfs
- Pros
- ZFS has realtime parity.
- ZFS can work while degraded.
- ZFS snapshots with send and receive.
- ZFS has encryption on per-dataset.
- ZFS handles everything altogether including parity on permissions
- Cons
- The main con is that ZFS is less expandable.
- You can only expand by replacing every drive or adding entire vdevs.
- If many drives die, i.e. >2 for raidz2, you lose all your data.