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ZFS file system

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According to wikipedia, ZFS stand for Z File System, which is an open source file system and a logical volume manager licensed under the Common Development and Distribution License.

Designed by Sun Microsystems (acquired by Oracle in 2009), and had been developed by Jeff Bonwick.

Main features

  • High storage capacity
  • Volume management
  • Data integrity
  • Snapshots and clones
  • Deduplication
  • Compression


Follow instructions for Debian on zfsonlinux website :


Create a ZFS pool

  • Get disks ids :
root@host:~# ls -lah /dev/disk/by-id/
  • Create mount point :
root@host:~# mkdir /zfs
  • Create RAID 0 :
root@host:~# zpool create -f -m <mount_point> <pool_name> <type> <ids>
root@host:~# zpool create -f -o ashift=12 -m /zfs raid0_01 mirror scsi-SATA_WDC_WD20EARS-07_WD-WCAZA796741 scsi-SATA_WDC_WD20EARS-07_WD-WCAZB7569258 scsi-SATA_WDC_WD20EARS-07_WD-WCPZB7464217
  • create : Create pool
  • -f : Force pool creation. (Avoid "EFI label error" error).
  • -o ashift=12 : align zpool on clusters size (current disks work with 4K or 8k not with 512k).
  • -m : Mounting point. / by default.
  • pool_name : Pool name.
  • type : Pool type. Example : mirror (raid0), raidz3, raidz2 etc…
  • ids : Disks names included inside the pool (see /dev/disk/by-id directory).
  • Add a hot disk spare :
root@host:~# zpool add tank spare ada12
  • List pools :
root@host:~# zpool list
  • Print commands pool history :
root@host:~# zpool history raid0_01
  • Change pool mount point :
root@host:~# zfs set mountpoint=/zfs raid0_01
  • If the zfs volume doesn't mount on new system :
root@host:~# zpool export raid0_01
root@host:~# zpool import -a
  • Or
root@host:~# zpool import -f raid0_01
  • Disable atime :
root@host:~# zfs set atime=off <pool>
  • Enable lz4 compression :
root@host:~# zfs set compression=lz4 <pool>
  • Enable zstd compression :
root@host:~# zfs set compression=zstd <pool>
  • Destroy a storage pool :

⚠️ this command destroys any data containing in the pool ⚠️

root@host:~# zfs destroy <pool>


Files system check (chkdsk equivalent)

  • Run a files system check :
root@host:~# zpool scrub raid0_01
  • Print datas check status :
root@host:~# zpool status
  • Clear the log :
root@host:~# zpool clear raid0_01

Print options

root@host:~# zfs get all <pool>

Replace drive in a RAID :

root@host:~# zpool replace pool1 ata-WDC_WD80EFZX-18ZW3NB_Z3K44HMB ata-ST8000DM002-1ZW212_ZX41X5MS


  • Print every pool informations :
root@host:~# zpool get all raid0_01
  • Print partition state :
root@host:~# zpool status -v raid0_01
  • Print IOs informations :
root@host:~# zpool iostat <second rate> <output number>
root@host:~# zpool iostat 5 10


Encryption with dm-crypt

Disks encryption

root@host:~# cryptsetup --cipher aes-xts-plain64 --key-size 512 --hash sha1 --iter-time 1000 --use-urandom -v luksFormat /dev/sdb1
root@host:~# cryptsetup --cipher aes-xts-plain64 --key-size 512 --hash sha1 --iter-time 1000 --use-urandom -v luksFormat /dev/sdc1
root@host:~# cryptsetup --cipher aes-xts-plain64 --key-size 512 --hash sha1 --iter-time 1000 --use-urandom -v luksFormat /dev/sdd1

Open encrypted disks

root@host:~# cryptsetup luksOpen /dev/sdb1 zfs01
root@host:~# cryptsetup luksOpen /dev/sdc1 zfs01
root@host:~# cryptsetup luksOpen /dev/sdd1 zfs01

ZFS pool creation

root@host:~# zpool create -f -m /zfs raid0_01 mirror /dev/mapper/zfs01 /dev/mapper/zfs02 /dev/mapper/zfs03

Native encryption

Creating zfs pool

root@host:~# zpool create -f -m /zfs raid0_01 pci-0000:03:00.0-scsi-0:0:1:0-part1

Create dataset including native encryption

root@host:~# zpool create -o encryption=on -o keyformat=passphrase raid0_01/dataset01

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