Many VPS plans support attaching additional block storage volumes beyond the primary disk. This guide covers formatting and mounting an additional disk on Linux.
Step 1 — Identify the New Disk
lsblkLists all block devices — identify the new, unformatted disk (typically shown with no filesystem type and no mount point), commonly something like /dev/sdb or /dev/vdb.
Step 2 — Verify It's Genuinely Unused (Important)
sudo fdisk -l /dev/sdbDouble-check you've identified the correct, new disk before proceeding — formatting the wrong disk destroys its existing data irreversibly.
Step 3 — Create a Partition (Optional but Common)
sudo fdisk /dev/sdbn # new partition
p # primary
1 # partition number
# accept default first/last sector
w # write changesYou can also format the raw disk directly without partitioning for simpler single-purpose volumes — partitioning offers more flexibility if you might later divide the disk further.
Step 4 — Format the Partition with a Filesystem
sudo mkfs.ext4 /dev/sdb1ext4 is a solid, widely-used default; XFS is another common choice, sometimes preferred for very large filesystems or specific performance characteristics.
Step 5 — Create a Mount Point
sudo mkdir /mnt/dataStep 6 — Mount the Disk
sudo mount /dev/sdb1 /mnt/dataStep 7 — Verify the Mount
df -h /mnt/dataStep 8 — Make the Mount Persistent Across Reboots
A mount performed manually doesn't survive a reboot unless added to /etc/fstab:
sudo blkid /dev/sdb1sudo nano /etc/fstabUUID=your-disk-uuid-here /mnt/data ext4 defaults 0 2Using the UUID (rather than the device name like /dev/sdb1) is more reliable, since device naming can occasionally shift between boots depending on detection order.
Step 9 — Test the fstab Entry
sudo umount /mnt/data
sudo mount -amount -a mounts everything listed in fstab — if this succeeds without errors, your entry is correctly configured and will work on the next actual reboot.
Setting Correct Ownership and Permissions
sudo chown -R youruser:yourgroup /mnt/dataResizing an Existing Disk (After a Provider-Side Expansion)
sudo growpart /dev/sdb 1
sudo resize2fs /dev/sdb1If your VPS provider expanded the underlying disk size, the partition and filesystem need to be separately resized to actually use the additional space.
Common Errors
"wrong fs type, bad option, bad superblock" on mount — verify the disk was actually formatted successfully in Step 4, and that the filesystem type specified in the mount command matches what was actually created.
System fails to boot after editing fstab — a malformed fstab entry can prevent boot; always test with mount -a before rebooting, and keep console/rescue access available as a fallback.
Continue Reading
- How to Check and Manage Disk Usage on a Linux VPS
- How to Enable and Configure Swap on a Linux VPS (Ubuntu & Debian)
- How to Clean Up Disk Space on a Linux VPS (Safe Practices)
Browse more articles in Linux Server Administration.
