Export/Import of ZFS Pools

How to move a pool from one machine to another.

I mowed a stack of disks from my old server to new server. It's the Proxmox Backup Server Datastore called bpool.

Another use case is when you experience a boot disk failure. As I use scripts to set up my systems it's really easy to throw in a new SSD, run a script and import the data pools. And in a few minutes I'm back.

Export

To export a ZFS pool is easy,

zpool import bpool -f

Import

To import an old pool to your Server

zpool import bpool -f

Check for success, zpool list

PBS - add it to your Datastore

nano /etc/proxmox-backup/datastore.cfg

Add the following

datastore: bpool
        gc-schedule daily
        notification-mode notification-system
        path /mnt/datastore/bpool

ZFS Cheat Sheet

Take an inventory of the drives available.

lsblk -o NAME,SIZE,MODEL,FSTYPE,LOG-SEC,PHY-SEC,SERIAL,MOUNTPOINT

NAME         SIZE  MODEL               FSTYPE         LOG-SEC PHY-SEC
sdc          14.6T ST16000NM000J-2TW123                    512    4096
sdd          14.6T ST16000NM000J-2TW456                    512    4096
sde          14.6T ST16000NM000J-2TW789                    512    4096
sdf          14.6T ST16000NM000J-2TW110                    512    4096
sdg          14.6T ST16000NM000J-2TW113                    512    4096

Create a basic ZFS file system

sudo zfs create tank/mydata

Create a file system with specific properties

sudo zfs create -o compression=lz4 -o recordsize=1M tank/database

Expected output:

# Filesystem created successfully (no output on success)
# Verify creation:
zfs list
NAME           USED  AVAIL     REFER  MOUNTPOINT
tank           156K   9.63G       24K  /tank
tank/database   24K   9.63G       24K  /tank/database
tank/mydata     24K   9.63G       24K  /tank/mydata

Listing ZFS Datasets

Display all ZFS datasets

zfs list

Show detailed information with specific properties

zfs list -o name,used,available,referenced,mountpoint,compression

Sample output:

NAME           USED  AVAIL     REFER  MOUNTPOINT        COMPRESS
tank           312K   9.63G       24K  /tank             on
tank/database   24K   9.63G       24K  /tank/database    lz4
tank/mydata     24K   9.63G       24K  /tank/mydata      on

Mounting and Unmounting

Mount a ZFS file system

sudo zfs mount tank/mydata

Unmount a file system

sudo zfs unmount tank/mydata

Set custom mount point

sudo zfs set mountpoint=/custom/path tank/mydata

Cloning Datasets

Create a clone from a snapshot

sudo zfs clone tank/mydata@backup-202606208 tank/mydata-clone

Renaming Datasets

sudo zfs rename tank/mydata tank/production-data

Monitoring and Troubleshooting

Checking Dataset Usage

zfs list -o space

Sample output:

NAME           AVAIL   USED  USEDSNAP  USEDDS  USEDREFRESERV  USEDCHILD
tank           9.63G   468K         0B    24K             0B       444K
tank/mydata    9.63G    24K         0B    24K             0B         0B

NAME                           AVAIL   USED  USEDSNAP  USEDDS  USEDREFRESERV  USEDCHILD
rpool                           175G  38.1G        0B    104K             0B      38.1G
rpool/ROOT                      175G  13.5G        0B     96K             0B      13.5G
rpool/ROOT/pve-1                175G  13.5G        0B   13.5G             0B         0B
rpool/data                      175G  23.6G        0B     96K             0B      23.6G
rpool/data/vm-100-disk-0        175G  1.29G        0B   1.29G             0B         0B
rpool/data/vm-1000-disk-0       175G  2.05G        0B   2.05G             0B         0B
rpool/data/vm-1000-disk-1       175G  76.4M        0B   76.4M             0B         0B
rpool/data/vm-102-disk-0        175G  1.42G        0B   1.42G             0B         0B
rpool/data/vm-1100-disk-0       175G   176M        0B    176M             0B         0B
rpool/data/vm-1100-disk-1       175G   135M        0B    135M             0B         0B
rpool/data/vm-1200-disk-0       175G    56K        0B     56K             0B         0B
rpool/data/vm-1300-disk-0       175G   100K        0B    100K             0B         0B
rpool/data/vm-1300-disk-1       175G  7.54G        0B   7.54G             0B         0B
rpool/data/vm-200-disk-0        175G    76K        0B     76K             0B         0B
rpool/data/vm-200-disk-1        175G  8.44G        0B   8.44G             0B         0B
rpool/data/vm-80000-cloudinit   175G    76K        0B     76K             0B         0B
rpool/data/vm-80000-disk-0      175G  2.49G        0B   2.49G             0B         0B
rpool/var-lib-vz                175G  1005M        0B   1005M             0B         0B

Property History

View property change history:

zfs get -H -o property,value,source all tank/mydata

Dataset Statistics

zfs get compressratio,used,referenced tank/mydata

Naming Conventions

• Use descriptive, hierarchical names: tank/application/database
• Include environment indicators: tank/web/production
• Use consistent snapshot naming: @backup-YYYYMMDD-HHMM

Space Issues

Investigate space usage

Check snapshot space usage

zfs list -t snapshot -o name,used,referenced

Check compression effectiveness

zfs get compressratio tank/mydata

Permission Problems

Reset permissions to defaults

sudo zfs unallow -r username tank/mydata

References

OpenZFS Admin Commands ^[1]