Gremoire

How to Add Extra Disks as VM Storage in Proxmox VE After Installation ​

When you install Proxmox VE with ZFS RAID1, the installer will use the disks you select (e.g., /dev/sda and /dev/sdb) to create the rpool system pool. Any other disks in the server (like /dev/sdc and /dev/sdd) remain untouched and unallocated.

The good news is you can still use those extra disks as dedicated storage for VMs and containers — without reinstalling Proxmox.

This guide shows you how to do exactly that.

Situation Example ​

  • Proxmox installed on:

    • /dev/sda (2.3 TB)
    • /dev/sdb (2.3 TB)
    • Configured as ZFS RAID1 (rpool)

  • Extra available disks:

    • /dev/sdc (2.4 TB)
    • /dev/sdd (2.4 TB)
    • Currently unallocated

Goal → Use /dev/sdc and /dev/sdd as VM storage in Proxmox.

Step 1: Verify the Disks ​

Check your available disks and pools:

bash
lsblk -o NAME,SIZE,FSTYPE,MOUNTPOINT
zpool status

You should see sda + sdb in rpool, and sdc + sdd free (maybe with NTFS or no FS).

Step 2: Wipe Old Partitions ​

Make sure the extra disks are clean:

bash
wipefs -a /dev/sdc
wipefs -a /dev/sdd

(optional: for a full wipe)

bash
sgdisk --zap-all /dev/sdc /dev/sdd

Step 3: Create a New ZFS Pool ​

Mirror the extra disks into a new pool named vmdata:

bash
zpool create vmdata mirror /dev/sdc /dev/sdd

Check the pool:

bash
zpool status

Step 4: Add the Pool to Proxmox ​

Tell Proxmox to use the new pool for VM images and containers:

bash
pvesm add zfspool vmdata -pool vmdata -content images,rootdir

Now if you run:

bash
pvesm status

You’ll see vmdata listed as active storage.

Step 5: Use the Storage ​

  • In the Proxmox Web UI → Datacenter → Storage, vmdata will appear.
  • When creating new VMs or LXCs, select vmdata as the target storage.

Alternative Options ​

  • Max capacity (no redundancy): use disks individually (zpool create vmdata1 /dev/sdc, etc.).
  • Directory storage (ext4): format a disk, mount it, then add with pvesm add dir ....

Final Result ​

  • rpool (ZFS RAID1): Proxmox system storage.
  • vmdata (ZFS mirror): Dedicated pool for VM and container storage.
  • Clean separation between system and workload disks.

Suggested Title ​

“How to Add Extra Disks as VM Storage in Proxmox VE After Installation”