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Using a new empty volume on a Linux VM

Data Loss Advisory

If this is not a newly created volume, the partition and format steps should be skipped as they will result in the loss of all existing data on that volume. Only the steps to mount the volume should be followed in such cases.

  1. Create a partition on the volume: 

    sudo fdisk /dev/vdb
    fdisk will prompt you to enter a command. Use the following sequence of single-character commands to create a new partition on your volume:

    • n: Create a new partition
    • p: Specify it as a primary partition (there will only be one partition on this disk)
    • 1: Assign partition number 1
    • <return>: Accept the default for the first sector
    • <return>: Accept the default for the last sector
    • w: Write the partition table to disk and exit

  2. Format the newly created partition: 

    sudo mkfs -t ext4 /dev/vdb1

  3. Create a mount point for the device: 

    sudo mkdir /media/data

  4. Finally, mount the volume: 

    sudo mount /dev/vdb1 /media/data

If the VM is rebooted for some reason, the volume will need to be remounted. To configure the VM to mount the volume automatically at boot time, edit /etc/fstab and add a line like this:

/dev/vdb1 /media/data ext4 defaults 0 2

For more details about the fstab file, refer to this Wikipedia article. If you are not rebooting, you can mount the device just added to /etc/fstab immediately with:

sudo mount -a

Unmounting a Volume or Device

If you need to remove a volume or other device for some reason, for example, to create an image from it, or to attach it to a different VM, it is best to unmount it first. Unmounting a volume before detaching it helps prevent data corruption.

To unmount our previously mounted volume, use the following command:

sudo umount /media/data

This command will work if no files are being accessed by the operating system or any other program running on the VM. This can include both reading and writing to files. If this is the case, when you try to unmount a volume, you will receive a message indicating that the volume is still busy, and it will not be unmounted.