Mounting New Data Disks on Azure Linux Virtual Machine

Mounting the data disk on Azure Linux Virtual Machine for seamless storage expansion!

When working with Virtual Machines (VMs) in the Azure cloud, it’s essential to ensure your data persists even during maintenance or resizing activities. In this guide, we’ll walk through the steps to attach a persistent disk to your Linux VM, format it, and set it up for automatic remounting after reboots.

SSH into your VM

Connect to your VM using SSH. Replace <username> and <PublicIP> with your VM credentials.

ssh <username>@<PublicIP>

If you use a PEM file for authentication.

ssh -i <PEMFile> <username>@<PublicIP>

Find the disk

Use lsblk to identify the disk you want to attach. In this example, sdc is the target disk with a size of 50GB.

lsblk -o NAME,HCTL,SIZE,MOUNTPOINT | grep -i "sd"

The output is similar to the following example

sda     0:0:0:0      30G
├─sda1             29.9G /
├─sda14               4M
└─sda15             106M /boot/efi
sdb     1:0:1:0      14G
└─sdb1               14G /mnt
sdc     3:0:0:0      50G

Here, sdc is the disk we want because it has a capacity of 50GB.

Format the disk

Use parted and mkfs.xfs to format the disk (/dev/sdc in this example).

sudo parted /dev/sdc --script mklabel gpt mkpart xfspart xfs 0% 100%
sudo partprobe /dev/sdc
sudo mkfs.xfs /dev/sdc1

Mount the disk

Create a directory and mount the filesystem.

sudo mkdir /datadrive
sudo mount /dev/sdc1 /datadrive

Persist the mount

To ensure automatic remounting after a reboot, add an entry to /etc/fstab. Find the UUID using blkid.

sudo blkid

Example Output

/dev/sda1: LABEL="cloudimg-rootfs" UUID="11111111-1b1b-1c1c-1d1d-1e1e1e1e1e1e" TYPE="ext4" PARTUUID="1a1b1c1d-11aa-1234-1a1a1a1a1a1a"
/dev/sda15: LABEL="UEFI" UUID="BCD7-96A6" TYPE="vfat" PARTUUID="1e1g1cg1h-11aa-1234-1u1u1a1a1u1u"
/dev/sdb1: UUID="22222222-2b2b-2c2c-2d2d-2e2e2e2e2e2e" TYPE="ext4" TYPE="ext4" PARTUUID="1a2b3c4d-01"
/dev/sda14: PARTUUID="2e2g2cg2h-11aa-1234-1u1u1a1a1u1u"
/dev/sdc1: UUID="33333333-3b3b-3c3c-3d3d-3e3e3e3e3e3e" TYPE="xfs" PARTLABEL="xfspart" PARTUUID="c1c2c3c4-1234-cdef-asdf3456ghjk"

Here, sdc1 we want to persist the mount.

Next, open the /etc/fstab file in a text editor.

sudo nano /etc/fstab

Add a line to the end of the file, using the UUID value for the /dev/sdc1 device that was created in the previous steps, and the mountpoint of /datadrive. Using the example from this article, the new line would look like the following

UUID=33333333-3b3b-3c3c-3d3d-3e3e3e3e3e3e   /datadrive   xfs   defaults,nofail   1   2

When you’re done editing the file, save and close the editor.

Alternatively, you can run the following command to add the disk to the /etc/fstab file

echo "UUID=33333333-3b3b-3c3c-3d3d-3e3e3e3e3e3e   /datadrive   xfs   defaults,nofail   1   2" >> /etc/fstab

Setting Ownership

Change ownership of the /datadrive directory to azureuser.

sudo chown -R azureuser:azureuser /datadrive

This sets the owner and group of the /datadrive directory and its contents to azureuser.

By following these steps, you’ve successfully attached a persistent disk to your Linux VM in Azure, formatted it, and set up automatic remounting for data persistence across reboots. This ensures your crucial data remains intact even during VM maintenance or resizing operations.