Linux VPS Storage Disk Setup: fdisk Partition, Btrfs Format, and fstab Config

I bought a GreenCloud (aff) Storage VPS on Black Friday!

A step-by-step walkthrough on using fdisk to partition disks on Linux (Ubuntu/Debian), formatting them to the Btrfs filesystem, and configuring /etc/fstab to ensure auto-mounting after reboots. This workflow can be used for all KVM-based VPS.

The following commands are run as root. If you don’t have sufficient permissions, remember to add sudo.

1. Use lsblk to see which disk needs partitioning

> lsblk
NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
sda      8:0    0  368K  1 disk 
sr0     11:0    1 1024M  0 rom  
vda    254:0    0   20G  0 disk 
|-vda1 254:1    0    1M  0 part 
|-vda2 254:2    0  122M  0 part /boot/efi
`-vda3 254:3    0 19.9G  0 part /
vdb    254:16   0  500G  0 disk

2. Use fdisk to create a partition

> fdisk /dev/vdb

Command (m for help): g
Command (m for help): n
For one partition, just use the default values.
Command (m for help): w
This writes the partition table changes stored in memory to the disk and then exits fdisk. If you exit before typing w, no changes will be made.

Welcome to fdisk (util-linux 2.41).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

Device does not contain a recognized partition table.
Created a new DOS (MBR) disklabel with disk identifier 0x0c3294a3.

Command (m for help): g

Created a new GPT disklabel (GUID: E5606734-1335-4696-9501-B9A12D5B780B).

Command (m for help): n
Partition number (1-128, default 1): 1
First sector (2048-1048575966, default 2048): 
Last sector, +/-sectors or +/-size{K,M,G,T,P} (2048-1048575966, default 1048573951): 

Created a new partition 1 of type 'Linux filesystem' and of size 500 GiB.

Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.

3. To use btrfs, install btrfs-progs

> apt install btrfs-progs

4. Format as btrfs

At this point, the output of lsblk should look like this:

NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
sda      8:0    0  368K  1 disk 
sr0     11:0    1 1024M  0 rom  
vda    254:0    0   20G  0 disk 
|-vda1 254:1    0    1M  0 part 
|-vda2 254:2    0  122M  0 part /boot/efi
`-vda3 254:3    0 19.9G  0 part /
vdb    254:16   0  500G  0 disk 
`-vdb1 254:17   0  500G  0 part

Run the format command:

> mkfs.btrfs -f /dev/vdb1
btrfs-progs v6.14
See https://btrfs.readthedocs.io for more information.

Performing full device TRIM /dev/vdb1 (500.00GiB) ...
NOTE: several default settings have changed in version 5.15, please make sure
      this does not affect your deployments:
      - DUP for metadata (-m dup)
      - enabled no-holes (-O no-holes)
      - enabled free-space-tree (-R free-space-tree)

Label:              (null)
UUID:               518709cc-6e80-43bf-afc9-bd2bd9a9791a
Node size:          16384
Sector size:        4096	(CPU page size: 4096)
Filesystem size:    500.00GiB
Block group profiles:
  Data:             single            8.00MiB
  Metadata:         DUP               1.00GiB
  System:           DUP               8.00MiB
SSD detected:       no
Zoned device:       no
Features:           extref, skinny-metadata, no-holes, free-space-tree
Checksum:           crc32c
Number of devices:  1
Devices:
   ID        SIZE  PATH     
    1   500.00GiB  /dev/vdb1

5. Mount to a specific path

I chose /mnt/backups.

> mkdir -p /mnt/backups
> mount -o compress=zstd /dev/vdb1 /mnt/backups
> lsblk
NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
sda      8:0    0  368K  1 disk 
sr0     11:0    1 1024M  0 rom  
vda    254:0    0   20G  0 disk 
|-vda1 254:1    0    1M  0 part 
|-vda2 254:2    0  122M  0 part /boot/efi
`-vda3 254:3    0 19.9G  0 part /
vdb    254:16   0  500G  0 disk 
`-vdb1 254:17   0  500G  0 part /mnt/backups

To allow a regular (non-root) user to read and write to this directory, chown it to the actual username. For example, if the username is small:

> chown -R small:small /mnt/backups

6. Edit fstab

To keep the settings after a reboot, we need to add it to fstab.

Locate the UUID by:

> blkid /dev/vdb1
/dev/vdb1: UUID="518709cc-6e80-43bf-afc9-bd2bd9a9791a" UUID_SUB="6593363f-aee9-493d-b912-49f84f9effcc" BLOCK_SIZE="4096" TYPE="btrfs" PARTUUID="15bcaff2-b553-4711-94cd-95f81a2c9093"

Edit /etc/fstab:

> nano /etc/fstab

Add the following to the end of the file:

UUID=518709cc-6e80-43bf-afc9-bd2bd9a9791a  /mnt/backups  btrfs  defaults,compress=zstd  0  0

UUID=…: Identifies the disk accurately.
/mnt/backups: Where it should live.
btrfs: The filesystem type.
defaults,compress=zstd: The options.
0 0: These last two numbers tell Linux not to “dump” the disk and not to scan it during boot (since Btrfs handles its own scanning).

7. Verify the fstab changes

> mount -a

Not output means it worked!

If there’s output, for example, if the UUID is wrong, the error message might look like this:

mount: /mnt/backups: can't find UUID=a1b2c3d4-1234-5678-9abc-def123456789.

8. Running YABS

If you want to run YABS (Yet Another Bench Script), cd into /mnt/backups and run YABS there to test this specific disk.