ZFS administration

ZFS administration

Some useful ZFS commands

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linux nas ubuntu zfs

Overview

There are lots of ways to manage your ZFS pools. This article contains some useful commands and examples. They are suitable for any kind of virtual device configuration including mirrored, RAIDZ or nonredundant.

Status

Check the health of all pools.

sudo zpool list
NAME      SIZE  ALLOC   FREE  EXPANDSZ   FRAG    CAP  DEDUP  HEALTH  ALTROOT
DUMPSTER  10.9T  1.45T  9.43T         -     0%    13%  1.00x  ONLINE  -

Check the health of a specific pool.

sudo zpool status DUMPSTER
  pool: DUMPSTER
 state: ONLINE
  scan: resilvered 235G in 2h10m with 0 errors on Sun Apr  5 15:26:31 2020
config:

        NAME        STATE     READ WRITE CKSUM
        DUMPSTER    ONLINE       0     0     0
          raidz1-0  ONLINE       0     0     0
            sdb     ONLINE       0     0     0
            sdc     ONLINE       0     0     0
            sdd     ONLINE       0     0     0
            sde     ONLINE       0     0     0
            sdf     ONLINE       0     0     0
            sdg     ONLINE       0     0     0

errors: No known data errors

Permissions

Check permissions

ls -ld /DUMPSTER
drwxr-xr-x 2 root root 2 Mar 23 08:49 /DUMPSTER

By default, the mount point of your ZFS pool is only writable by root.

Change permissions

Set the user and group on the mount point of our pool.

sudo chown -Rfv myusername:mygroupname /DUMPSTER
changed ownership of '/DUMPSTER' from root:root to myusername:mygroupname

Mount point

Check mount point

df -h | grep DUMPSTER
DUMPSTER        5.2T  128K  5.2T   1% /DUMPSTER

The default mount point for a ZFS pool is /mypool.

Change mount point

sudo zfs set mountpoint=/var/storage DUMPSTER

You can set the mount point to any location. If the directory doesn't already exisit then you should create it first.

Destroy

All data in the pool will be lost!

If the pool contains important data, then back-up that data before proceeding.

sudo zpool destroy DUMPSTER

Rename

There is no rename command. However, we can rename a pool by exporting it, then importing it with a new name.

sudo zpool export DUMPSTER

Now we can import the same pool whilst applying a new name.

sudo zpool import DUMPSTER TRUCK

Check that the renaming has been successful.

sudo zpool list
NAME     SIZE  ALLOC   FREE  EXPANDSZ   FRAG    CAP  DEDUP  HEALTH  ALTROOT
TRUCK   10.9T  1.45T  9.43T         -     0%    13%  1.00x  ONLINE  -

Share

Share using Samba

Samba, using the SMB protocol, allows you to share your ZFS pool with other clients.

First we need to install Samba.

sudo apt-get update
sudo apt install samba

Then turn on Samba sharing for our ZFS pool.

sudo zfs set sharesmb=on DUMPSTER

This will create a file within /var/lib/samba/usershares called yourpool, in this case DUMPSTER.

Make sure you add your user to the Samba database

sudo smbpasswd -a dave

Please read how to create a Samba network share for more information.