ZFS storage

ZFS pools and datasets on a managed Linux machine are built on the ZFS storage tab, which also shows the health of every disk. It shows what the machine reports, and each button acts at the press; the hub keeps no list of wanted pools.

To prepare the tab, select Install and then Configure on the ZFS storage tab of the Modules page. The install also brings smartmontools.

Create a pool

1. Under Pools, select Create pool.
2. Fill Pool name.
3. Under First vdev disks, pick the disks.
4. Under Vdev layout, pick Single, Mirror, RAID-Z1 or RAID-Z2. A layout unlocks when enough disks are picked.
5. If the picked disks hold data, type wipe to erase them.
6. Select Create pool.

A vdev is a group of disks in the pool. Single has no redundancy, Mirror keeps full copies, and RAID-Z1 and RAID-Z2 survive one and two failed disks. Expand adds another vdev to a pool for good.

WARNING

A new vdev whose layout differs from the pool's other vdevs leaves the pool only as safe as its weakest vdev. Adding one takes a second press, on Add anyway.

A pool on attached disks that this machine has not imported shows an Import button. Destroy pool erases every dataset after you type the pool's name.

Disk health

Topology draws each pool's vdevs and disks, and lists unused disks as UNASSIGNED. Each disk reads SMART ok or SMART FAILING; select one to see its details.

• Scrub checks every block of a pool against its checksums.
• Offline takes a selected disk out of its pool for a while, and Online puts it back.
• Replace lists the spare disks; pick one and select Start resilver to rebuild onto it.

Datasets

1. Under Datasets, select Add dataset.
2. Pick the Pool and fill the Name.
3. Optional: set a Mountpoint. Left blank, it is /pool/name.
4. Pick the Compression and the Record size. Small records suit databases and VM images, large ones media.
5. Select Create dataset.

Destroy on a row removes the dataset and every file on it.

To share a mounted dataset, the File share module must run on the same machine. Select Share on the row, pick the users, or none for every user, and select Share again. The row then has an smb badge, and Unshare withdraws it.