Multi-Drive VMs

A single root drive is enough for most use cases, but topics like disk partitioning, LVM, RAID, or filesystem comparisons call for VMs with several block devices. Adding drives to a playground machine is a one-liner per drive:

kind: playground
name: storage-lab
title: Storage Lab
playground:
  machines:
    - name: storage-01
      users:
        - name: laborant
          default: true
      drives:
        - source: ubuntu-24-04
          mount: /
          size: 10GiB
        - mount: /mnt/data
          size: 5GiB
        - mount: /mnt/scratch
          size: 5GiB
          filesystem: xfs
        - size: 20GiB
      network:
        interfaces:
          - network: local
      resources:
        cpuCount: 2
        ramSize: 2GiB
  accessControl:
    canList:
      - owner
    canRead:
      - owner
    canStart:
      - owner

labctl playground create storage-lab --base flexbox -f manifest.yaml

Playground VMs can be used to simulate complex server setups - pick a kernel and a rootfs, add extra drives with different filesystems, configure multiple networks, etc.

How drives work

• Device names follow the list order: the first drive becomes /dev/vda, the second /dev/vdb, and so on.
• Exactly one drive must have mount: / - that's the root drive, and it's the only drive that requires a source (a rootfs image to build the filesystem from).
• Extra drives are optional in every respect. Omit source to get an empty drive. Drives with a mount are formatted (with ext4 unless filesystem says otherwise) and mounted automatically at boot via /etc/fstab - the mount directory is created for you.
• A drive with neither source nor mount nor filesystem (like the 20 GiB one above) is attached as a raw, unformatted block device - perfect for practicing fdisk, mkfs, and friends. Specify filesystem without mount if you want the drive pre-formatted but not mounted.
• Supported filesystems: ext4 (default), ext2, ext3, xfs, and btrfs.

Verify the result from inside the playground:

lsblk -f

NAME FSTYPE FSVER LABEL UUID                                 FSAVAIL FSUSE% MOUNTPOINTS
vda  ext4   1.0         a9928411-dea4-472c-9109-c1a334bcb8ab    7.6G    17% /
vdb  ext4   1.0         bb6438a0-a96c-4965-9b31-4837d8b6a9a0    4.4G     0% /mnt/data
vdc  xfs                e7d3bc38-8b7a-45d3-85ff-c6254da83cc3    4.8G     3% /mnt/scratch
vdd

Sizes and limits

• If size is omitted, the platform default applies (the defaults depend on the base playground).
• A drive can be from 1 GiB to 50 GiB, and the total across all drives of a playground must stay within 150 GiB.
• A machine can have up to 24 drives.

The same drive configuration can also be assembled in the Playground Constructor UI - each machine's Drives section offers the identical source/mount/size/filesystem knobs.

Additional Resources

• 🎯 Disk partitioning challenges - to see multi-drive playgrounds in action