How to import ZFS pool with duplicated pool names

If you use ZFS as the file system, you probably already know that tank is the most common name for ZFS pools. That also applies to me, I do name most of my ZFS pools as tank as the default. There is no issue with that name, however, since ZFS’s pool name must be unique, this means I couldn’t import or have multiple ZFS pools with the name tank on a system.

So what can we do if we need to import 2 ZFS pools for some reasons? Well, we can temporarily name the additional pools with different names.

The following will demonstrate how can this be done on a live XCP-NG server.

First, list the current imported ZFS pool on the server, named tank, of course, running on /dev/sda device.

[18:51 xcpng ~]# zpool status
  pool: tank
 state: ONLINE
config:

        NAME        STATE     READ WRITE CKSUM
        tank        ONLINE       0     0     0
          sda       ONLINE       0     0     0

errors: No known data errors

Next, list the available pool to be imported.

[18:51 xcpng ~]# zpool import
   pool: tank
     id: 17451229533051529435
  state: ONLINE
 action: The pool can be imported using its name or numeric identifier.
 config:

        tank        ONLINE
          sdc       ONLINE

For fun, let’s try to import the second tank pool on the /dev/sdc device.

[18:52 xcpng ~]# zpool import tank
cannot import 'tank': a pool with that name already exists
use the form 'zpool import <pool | id> <newpool>' to give it a new name

Well, we already knew that, didn’t we? The output of the command also suggested to imported the pool as a new name. That would work, but I want to keep the pool name as tank after I exported this device.

At this stage, we can decide to import the tank pool on /dev/sdc as temporary name tanktemp. Here is how we can do this.

[18:56 xcpng ~]# zpool import 17451229533051529435 -t tanktemp

[18:56 xcpng ~]# zpool status
  pool: tank
 state: ONLINE
config:

        NAME        STATE     READ WRITE CKSUM
        tank        ONLINE       0     0     0
          sda       ONLINE       0     0     0

errors: No known data errors

  pool: tanktemp
 state: ONLINE
config:

        NAME        STATE     READ WRITE CKSUM
        tanktemp    ONLINE       0     0     0
          sdc       ONLINE       0     0     0

errors: No known data errors

That’s it. The additional tank pool has been successfully imported it to a temporary name tanktemp with the -t option.