How to Mount and Unmount Volumes

Every time you attach a volume to a Droplet, you need to mount it. Mounting a formatted volume adds the volume’s filesystem to the Droplet’s existing file hierarchy. You need to mount a volume every time you attach it to a Droplet to make it accessible to that Droplet’s operating system.

Alternatively, you can choose to automatically format and mount it to a Droplet with a supported operating system.

You can also set up persistent mounting to tell the operating system to mount certain filesystems on boot, which lets volumes remain accessible after reboots.

Before you mount your volume, you need to format it once. Formatting a volume creates a filesystem on the volume, erasing any existing data.

Mount a Volume

To mount a volume, choose a mount point, which is the directory where the volume’s filesystem should be attached. This is where you access the volume’s files after it’s mounted.

We recommend creating a new directory in /mnt to use as a mount point:

sudo mkdir /mnt/example_mount_point

Next, use mount to mount the volume’s filesystem to the mount point. We recommend using the same options as automatic mounting, which are defaults,nofail,discard,noatime:

sudo mount -o defaults,nofail,discard,noatime /dev/disk/by-id/scsi-example /mnt/example_mount_point

These options include read/write access, executing programs, error suppression for nonexistent devices, and continuous TRIM, which improves performance and reduces unnecessary disk writes. Use mount’s man page (man mount) for more details about these options and all other mount options.

You can check that the mount itself was successful by passing the mount point to findmnt:

findmnt /mnt/use_your_mount_point

A successful output shows that the volume is currently mounted like this:

TARGET                   SOURCE    FSTYPE OPTIONS
/mnt/example_mount_point /dev/sda1 ext4   rw,noatime,discard,data=ordered

Set Up Persistent Mounting

The /etc/fstab file contains static information about filesystems that the operating system can mount, including which ones to mount automatically at boot. You can add a line to this file for the volume’s filesystem to make it mount automatically when the Droplet boots. This keeps the volume’s filesystem persistent through reboots.

Each line in /etc/fstab represents one filesystem and consists of six fields:

• fs_spec, the block device to mount. Use the /dev/disk/by-id identifier for the volume or partition.
• fs_file, the mount point for the filesystem.
• fs_vfstype, the type of filesystem in lowercase, like ext4 or xfs.
• fs_mntops, the mount options. We recommend the same options as automatic mounting, defaults,nofail,discard,noatime. nofail in particular lets the operating system continue its boot sequence if the filesystem can’t be found, which is helpful if you detach the volume in the future without removing its fstab entry.
• fs_freq, whether dump should operate on the filesystem. Use 0 to disable this functionality unless you know you need it.
• fs_passno, the order that fsck should check filesystems in. Use 2 to enable checking. The root filesystem should be 1, and 0 disables checking.

The line you add to /etc/fstab should look like this, with your volume’s identifier and mount point:

/dev/disk/by-id/scsi-example /mnt/example-mount-point ext4 defaults,nofail,discard,noatime 0 2

After you edit the file, check that /etc/fstab is parsable and usable:

findmnt --verify --verbose

This lists any parsing errors, execution errors, and warnings. Once you resolve all errors, you can use mount -a to mount the volume.

Unmount a Volume

If needed, you can unmount a volume to make its filesystem inaccessible to its Droplet’s operating system. This means the operating system can’t write to or read from the volume. You should unmount volumes before resizing or detaching them to protect data integrity.

To unmount a volume, get the volume’s mount point with df:

sudo df --human-readable --print-type

The mount point looks like /mnt/volume-sfo2-01, for example:

Filesystem     Type      Size  Used Avail Use% Mounted on
...
/dev/sda       ext4       99G   60M   94G   1% /mnt/volume-sfo2-01
...

Then, ensure the volume isn’t in use. If you try to unmount a volume while it’s in use, you get a target is busy error, so check if any processes are using the volume with lsof:

sudo lsof +f -- /mnt/use_your_mount_point

If there are any processes using the volume, stop any listed processes by stopping the services or processes that are accessing the mount point. For example, stop the service using systemctl stop <service-name> or terminate the process with kill.

Unmount the volume with umount:

sudo umount --verbose /mnt/use_your_mount_point

Including the --verbose flag makes the command output /mnt/your_mount_point unmounted when it executes successfully. Otherwise, umount is silent on successful execution.

A successful unmount looks like this:

/mnt/use_your_mount_point unmounted

If you plan not to reattach the volume, you can also edit the /etc/fstab to remove any entries referencing the volume, and also delete the mount point.

To edit /etc/fstab to remove any entries referencing the volume, open the file using a text editor of your choice, such as nano or vi, and delete the line that references the volume’s /dev/disk/by-id identifier.

This is successful if the file saves without errors and findmnt --verify reports no issues.

To delete the mount point, run the following command to remove the directory:

sudo rmdir /mnt/use_your_mount_point

Verify the mount point is deleted by running ls /mnt and confirming the directory no longer appears in the output.