ZFS - Pools - Create a ZFS Pool - Comprehensive Steps to Create a ZFS Pool

Choose Drives to Pool

Check installed drives by running:

sudo fdisk -l

returns:

Disk /dev/sdb: 14.57 TiB, 16000900661248 bytes, 31251759104 sectors
Disk model: ST16000NM001G-2K
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
 
Disk /dev/sdc: 14.57 TiB, 16000900661248 bytes, 31251759104 sectors
Disk model: ST16000NM001G-2K
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes

NOTE: Note down the device names of drives you want to pool.

Another method to check the disks:

lsblk -S

returns:

NAME HCTL       TYPE VENDOR   MODEL                 REV TRAN
sdb  5:0:0:0    disk ATA      ST16000NM001G-2KK103 SN02 sata
sdc  8:0:0:0    disk ATA      ST16000NM001G-2KK103 SN02 sata

WARNING: Ensure that the disk with the Ubuntu operating system is not used.

Also exclude any other disks that may contain data not to be destroyed.

Delete Existing Partitions if required

Delete all partitions and reset it:

sudo sgdisk - -zap-all /dev/sdb

Create a partition with 1GB of trailing free space:

sudo sgdisk -n1:0:-1G -t1:BF00 /dev/sdb

NOTE: Adjust these values as required.

NOTE: This will result in a /dev/sdb1 partition being created.

Creating a Pool

Different types of storage pools can be created:

To create a striped pool

sudo zpool create testpool /dev/sdb /dev/sdc

NOTE: This is equivalent to RAID0.

This has no parity and no mirroring to rebuild the data.
This is not recommended because of the risk of losing data if a drive fails.

To create a mirrored pool

sudo zpool create testpool mirror /dev/sdb /dev/sdc

NOTE: Much like RAID1, one can use 2 or more VDEVs.

For N VDEVs, one will have to have N-1 fail before data is lost.

To create a Striped Mirrored VDEVs

sudo zpool create example mirror /dev/sdb /dev/sdc mirror /dev/sdd /dev/sde
 
or
 
sudo zpool create example mirror /dev/sdb /dev/sdc
sudo zpool add example mirror /dev/sdd /dev/sde

NOTE: Much like RAID10.

Great for small random read I/O.
Create mirrored pairs and then stripe data over the mirrors.
This creates striped 2 x 2 mirrored pool.

To create a RAIDZ pool

sudo zpool create testpool mirror /dev/sdb /dev/sdc
sudo zpool create example raidz /dev/sdb /dev/sdc /dev/sdd /dev/sde

NOTE: Like RAID5.

This uses a variable width strip for parity.
Allows one to get the most capacity out of a bunch of disks with parity checking with a sacrifice to some performance.
Allows a single disk failure without losing data.

To create a RAIDZ2 pool

sudo zpool create example raidz2 /dev/sdb /dev/sdc /dev/sdd /dev/sde /dev/sdf

NOTE: Like RAID6.

Has double the parity for 2 disk failures with performance similar to RAIDZ.

To create a RAIDZ3 pool

sudo zpool create example raidz3 /dev/sdb /dev/sdc /dev/sdd /dev/sde /dev/sdf /dev/sdg

NOTE: Better than RAID6.

Has 3 parity bits, allowing for 3 disk failures before losing data with performance like RAIDZ2 and RAIDZ.

To create a Nested Raid pool

sudo zpool create example raidz /dev/sdb /dev/sdc /dev/sdd /dev/sde
sudo zpool add example raidz /dev/sdf /dev/sdg /dev/sdh /dev/sdi

NOTE: Like RAID50, RAID60, striped RAIDZ volumes.

This is better performing than RAIDZ but at the cost of reducing capacity.

NOTE: Here, entire disks are being used for the pool.

ZFS also supports creating pools from disk partitions, such as /dev/sdb1.
Anything with a descriptor in /dev that allows random access will work.
- Test pools made of sparse files are an incredibly convenient way to practice zpool commands.

NOTE: The newly mounted pool will appear as any other part of the filesystem.

testpool is the name of the pool.

The newly created pool will be mounted at /testpool.
- You can select a different mount point using the -m option:
```
sudo zpool create -m /mnt/testpool testpool mirror /dev/sdb /dev/sdc
```

NOTE: If any error appears, the command can be rerun with the -f option after the zpool create command which forces the command to be executed:

sudo zpool create -f testpool /dev/sdb /dev/sdd

NOTE: Advanced options can also be used when creating a pool.

sudo zpool create -f -o ashift=12 -O compression=lz4 my_pool /dev/sdb1

ashift: corresponds to 4k sector size.
compression: Enables LZ4 compression.
my_pool: The name of my new zpool.
/dev/sdb1: The disk partition to use for the pool.

List Mounts

Check the Mount is showing:

df -h

Set Permissions of the Mount

By default only root can write to the mounted directory.

Change this so that any ordinary user can make changes to the directory:

sudo chown -Rfv peter:peter /testpool

Check Pool Status

sudo zpool status

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