Tag: zfs

ZFS file system allow you to take snapshot, this is great for backing up MySQL databases. Last day i setup 2 * 2 TB Hard disk on My PC as RAID 1 (mirror) using ZFS.

First install ZFS with

apt install zfsutils-linux

I created same size partition on both hard disks. You can use full disk if you want, but i created partition, so i can use first 100 GB of each disk for installing Operating system.

RAID 1

RAID 1 mirror data between 2 disks. Even if one of the disk die, your data will be safe.

To create RAID 1, run

zpool create tank mirror /dev/sdx3 /dev/sdy3

Here sdx3 and sdy3 is partition on my HDD. Replace it with your actual partition to be used with ZFS. Be carefull not to use wrong partition or you will lose data.

If you are using full disk, then use

zpool create tank mirror /dev/sdx /dev/sdy

RAID 0

RAID 0 is dangerous, only use if you don’t care about data or you have a backup. If one of the disk fails, you will lose all data.

To setup RAID 0, use

zpool create tank /dev/sdx3 /dev/sdy3

Pool

Once you create a ZFS pool with “zpool” command, it get auto mounted as “/pool-name”. In above cause, i used name “tank”.

Here is what i have on my PC

root@ok-pc-01:~# df -h | grep tank
tank/data             1.6T  371G  1.3T  23% /mnt/data
tank                  1.3T     0  1.3T   0% /tank
root@ok-pc-01:~# 

The 2nd entry is the ZFS pool tank.

Datasets

Datasets are like partitions. You can create multiple partitions inside your pool, they sare disk space. You can set disk quotas if needed, by default no quota per datasets are set.

In above example /tank/data is a datasets i use.

To create a data set, run

zfs create -o mountpoint=/mnt/data tank/data

Here “-o mountpoint” specify where you want to mount the new dataset.

zpool status

To see status for your ZFS file system, run

root@ok-pc-01:~# zpool status
  pool: tank
 state: ONLINE
  scan: none requested
config:

	NAME        STATE     READ WRITE CKSUM
	tank        ONLINE       0     0     0
	  mirror-0  ONLINE       0     0     0
	    sda3    ONLINE       0     0     0
	    sdc3    ONLINE       0     0     0

errors: No known data errors
root@ok-pc-01:~# 

See zfs

Install zfs file system on Ubuntu

apt install -y zfs

Listing ZFS file systems

root@ns3048991:~# zfs list
NAME                       USED  AVAIL  REFER  MOUNTPOINT
rpool                     1.12T   654G   104K  /rpool
rpool/ROOT                5.50G   654G    96K  /rpool/ROOT
rpool/ROOT/pve-1          5.50G   654G  5.50G  /
rpool/data                1.11T   654G    96K  /rpool/data
rpool/data/vm-101-disk-0   103G   748G  9.29G  -
rpool/data/vm-101-disk-1  1.01T  1.65T    56K  -
rpool/swap                4.25G   658G   289M  -
root@ns3048991:~# 

List pools

root@ns3048991:~# zpool list
NAME    SIZE  ALLOC   FREE  EXPANDSZ   FRAG    CAP  DEDUP  HEALTH  ALTROOT
rpool  1.81T  15.4G  1.80T         -     0%     0%  1.00x  ONLINE  -
root@ns3048991:~# 

Show current IO usage

root@ns3048991:~# zpool iostat
              capacity     operations     bandwidth 
pool        alloc   free   read  write   read  write
----------  -----  -----  -----  -----  -----  -----
rpool       15.8G  1.80T     28     46   319K  2.14M
root@ns3048991:~# 

To see status

root@ns3048991:~# zpool status
  pool: rpool
 state: ONLINE
status: Some supported features are not enabled on the pool. The pool can
	still be used, but some features are unavailable.
action: Enable all features using 'zpool upgrade'. Once this is done,
	the pool may no longer be accessible by software that does not support
	the features. See zpool-features(5) for details.
  scan: none requested
config:

	NAME        STATE     READ WRITE CKSUM
	rpool       ONLINE       0     0     0
	  mirror-0  ONLINE       0     0     0
	    sda2    ONLINE       0     0     0
	    sdb2    ONLINE       0     0     0

errors: No known data errors
root@ns3048991:~# 

Setup ZFS file system in Ubuntu