Add a second disk to a VM

Volumes are standalone disks that live independently of any VM: create one, attach it, move it to another VM later. Same replicated NVMe fabric as root disks, same classes and speed tiers, hot-attach with no reboot.

Create and attach

The fastest path is from the VM itself:

  1. Open the VM and go to the Volumes tab
  2. Click Create + attach
  3. Pick a disk class (Basic covers most cases, Database for transactional loads, Solo for scratch, Storage for bulk) and a size
  4. Confirm. The volume is provisioned and attached in one step, while the VM keeps running

An existing detached volume attaches from the same tab with one click. Standalone creation without a VM lives under Volumes in the sidebar.

Format and mount (Linux)

The new disk appears in the guest immediately as the next virtio device, typically /dev/vdb. Check with lsblk, then create a filesystem and mount it:

Terminal 
lsblk
sudo mkfs.ext4 /dev/vdb
sudo mkdir -p /mnt/data
sudo mount /dev/vdb /mnt/data

To survive reboots, add it to /etc/fstab. The nofail option matters: without it a detached volume can drop the VM into emergency mode on boot:

Terminal 
echo '/dev/vdb /mnt/data ext4 defaults,nofail 0 2' | sudo tee -a /etc/fstab

Detach safely

Order matters. Unmount inside the guest first, then detach in the panel:

Terminal 
sudo umount /mnt/data
  1. Remove or comment the volume's /etc/fstab line if you added one
  2. In the VM's Volumes tab, click Detach

Detaching a mounted filesystem is the block-storage equivalent of yanking a USB drive mid-write: the disk itself is fine, but the filesystem may need repair and the last writes may be lost. Unmount first, every time.

A detached volume keeps its data and keeps billing for its size. Attach it to any other VM to get the data back, or delete it when you are done with it.

Growing and retiering

Volumes resize upward in place, and the speed class can be changed without moving data: both from the volume's menu in the panel. After growing a volume, extend the filesystem inside the guest (sudo resize2fs /dev/vdb for ext4).

What's next?