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
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.