How to Add a Backup Drive to a cPanel Server

Keeping cPanel backups on the same disk as the accounts is risky: if that disk fails, you lose both. A second disk, mounted at /backup, fixes that. This guide adds one to a cPanel server running AlmaLinux, CloudLinux or Ubuntu.

Quick answer

With the new, empty disk at /dev/sdb (check yours first in Step 1):

parted -s /dev/sdb mklabel gpt mkpart backup ext4 0% 100%
mkfs.ext4 -L backup /dev/sdb1
mkdir -p /backup
echo 'LABEL=backup  /backup  ext4  defaults,nofail  0  2' >> /etc/fstab
systemctl daemon-reload
mount /backup

Then check that WHM › Backup › Backup Configuration uses /backup as the Default Backup Directory. cPanel

What you need: root SSH access, and a new disk installed in the server (or attached to the VPS). Everything on that disk will be erased.

Step 1: Find the new disk

List the disks:

lsblk -o NAME,SIZE,TYPE,MOUNTPOINTS,MODEL

Example output:

NAME     SIZE TYPE MOUNTPOINTS MODEL
sda    447.1G disk             SSD 480GB
├─sda1     1G part /boot
└─sda2 446.1G part /
sdb    931.5G disk             HDD 1TB

The new disk is the one with the expected size and no partitions and no mount points, here sdb. On NVMe servers it is named like nvme1n1, and its first partition is nvme1n1p1 instead of sdb1.

Be certain you have the right disk: the next steps erase it. Replace /dev/sdb with your disk's name in every command below.

Step 2: Partition the disk

Create a GPT partition table and one partition that uses the whole disk:

parted -s /dev/sdb mklabel gpt mkpart backup ext4 0% 100%

GPT works for disks of any size. The older fdisk "DOS" layout cannot use more than 2 TB of a disk.

Check the result. sdb should now have one partition, sdb1:

lsblk /dev/sdb

Step 3: Format the partition

mkfs.ext4 -L backup /dev/sdb1

This creates an ext4 file system named (labelled) backup. XFS also works if you prefer it: mkfs.xfs -L backup /dev/sdb1.

Step 4: Mount it at /backup

If /backup already holds backups, move them aside first, so they are not hidden under the new disk:

mv /backup /backup.old

Create the mount point and add the disk to /etc/fstab, so it mounts at every boot:

mkdir -p /backup
echo 'LABEL=backup  /backup  ext4  defaults,nofail  0  2' >> /etc/fstab

If you formatted with XFS in Step 3, write xfs instead of ext4 in that line.

The nofail option lets the server finish booting even if the backup disk is missing or broken. Without it, a failed backup disk can stop the server from starting. systemd.mount

Mount it, and check for mistakes in /etc/fstab:

systemctl daemon-reload
mount /backup
findmnt --verify

findmnt --verify should report no errors. Then confirm the disk is mounted with its full size:

df -h /backup

If you moved old backups aside, move them onto the new disk now, then remove the empty folder:

mv /backup.old/* /backup/
rmdir /backup.old

Step 5: Point cPanel backups at it

1. In WHM, go to Backup › Backup Configuration.
2. Under Backup Directory, check that Default Backup Directory is /backup. That is cPanel's default. cPanel
3. Leave Mount Backup Drive as Needed off. With it on, cPanel mounts and unmounts the drive around each backup run, and the File and Directory Restoration tools in WHM and cPanel stop working. cPanel
4. Click Save Configuration.

The next scheduled backup is written to the new disk. To test now, run as root:

/usr/local/cpanel/bin/backup --force

When it finishes, ls /backup should show a folder named after today's date.

Troubleshooting

mount: /backup: can't find LABEL=backup. The partition was not formatted with the label. Run blkid /dev/sdb1 and check for LABEL="backup". Or use the UUID= value that blkid shows in /etc/fstab instead of LABEL=backup.

The server will not boot after editing fstab. Most likely a typo, or the line is missing nofail. Boot into rescue mode, fix or comment out the line in /etc/fstab with vi, and reboot.

Backups still fill the main disk. Check df -h /backup. If it shows the main disk's size, the new disk is not mounted. Run mount /backup and check findmnt --verify again.