Creating and configuring an additional disk on an instance
Find out how to attach a new volume to your Public Cloud instance
Last updated 9th February 2023
Objective
It is possible to create additional disks for your Public Cloud instances. This can be useful in cases where:
- You want to increase your storage capacity without changing the instance model.
- You want to have a highly available, high-performance storage.
- You want to move your storage as well as your data to another instance.
This guide explains how to create an additional disk and configure it on your instance.
Requirements
- Access to the OVHcloud Control Panel
- A Public Cloud Instance in your OVHcloud account
- Administrative (root) access to your instance via SSH (Linux) or RDP (Windows)
Instructions
Attaching a new volume
Log in to the OVHcloud Control Panel and open your Public Cloud project. Then open Block Storage in the left-hand menu.
In this section, click on the button Create a volume.
Follow the configuration steps in order to select options for location, disk type and disk capacity. Then enter a name for the volume and confirm by clicking on Create the volume.
The new disk will now be displayed in the Control Panel.
To the right of the volume, click on the ... button, then select Attach to instance.
In the popup window, choose an instance from the list and click on Confirm to attach the disk.
The process of attaching the disk to your instance will now begin. This may take a few minutes to complete.
Make sure to not leave the current page in your OVHcloud Control Panel while the disk is being attached. This might interrupt the process.
Configuring the new disk
The examples below presume you are logged in as a user with elevated permissions.
Using Linux
Establish an SSH connection to your instance, then use the command below to list the attached disks.
~$ admin@server-1:~$ lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
vda 254:0 0 10G 0 disk
└─vda1 254:1 0 10G 0 part /
vdb 254:16 0 10G 0 disk
vda in this example refers to the default disk of the instance. The additional disk will then be labelled vdb.
Create a partition on the additional disk using the commands below.
~$ admin@server-1:~$ sudo fdisk /dev/vdb
Welcome to fdisk (util-linux 2.25.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
Device does not contain a recognized partition table.
Created a new DOS disklabel with disk identifier 0x95c4adcc.
Command (m for help): n
Partition type
p primary (0 primary, 0 extended, 4 free)
e extended (container for logical partitions)
Select (default p):
Using default response p.
Partition number (1-4, default 1):
First sector (2048-20971519, default 2048):
Last sector, +sectors or +size{K,M,G,T,P} (2048-20971519, default 20971519):
Created a new partition 1 of type 'Linux' and of size 10 GiB.
Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.
Next, format the new partition vdb1 using the command below.
~$ admin@server-1:~$ sudo mkfs.ext4 /dev/vdb1
mke2fs 1.42.12 (29-Aug-2014)
Creating filesystem with 2621184 4k blocks and 655360 inodes
Filesystem UUID: 781be788-c4be-462b-b946-88429a43c0cf
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632
Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
Mount the partition with the following commands:
admin@server-1:~$ sudo mkdir /mnt/disk
admin@server-1:~$ sudo mount /dev/vdb1 /mnt/disk/
Finally, check the mount point using this command:
~$ admin@server-1:~$ df -h
Filesystem Size Used Avail Use% Mounted on
/dev/vda1 9.8G 840M 8.6G 9% /
udev 10M 0 10M 0% /dev
tmpfs 393M 5.2M 388M 2% /run
tmpfs 982M 0 982M 0% /dev/shm
tmpfs 5.0M 0 5.0M 0% /run/lock
tmpfs 982M 0 982M 0% /sys/fs/cgroup
/dev/vdb1 9.8G 23M 9.2G 1% /mnt/disk
The mounting is not persistent because the disk will be detached when the instance reboots. In order to automate the mounting process, the fstab file needs to be edited.
First, retrieve the UUID (block ID) of the new volume:
~$ admin@server-1:~$ sudo blkid
/dev/vda1: UUID="51ba13e7-398b-45f3-b5f3-fdfbe556f62c" TYPE="ext4" PARTUUID="000132ff-01"
/dev/vdb1: UUID="2e4a9012-bf0e-41ef-bf9a-fbf350803ac5" TYPE="ext4" PARTUUID="95c4adcc-01"
Open /etc/fstab with a text editor:
~$ sudo nano /etc/fstab
Add the line below to the file and replace the UUID with your own:
UUID=2e4a9012-bf0e-41ef-bf9a-fbf350803ac5 /mnt/disk ext4 nofail 0 0
Save and exit the editor. The disk should be automatically mounted after every reboot from now on.
Using Windows
Establish a remote desktop (RDP) connection to your Windows instance.
Once logged in, right-click on the Start Menu button and open Disk Management.
The new disk will be displayed as an unknown volume with unallocated space.
If the disk is marked as offline here, it needs to be initialised first. You can use the Windows GUI or the DISKPART utility to achieve this. Otherwise, proceed with formatting the disk in Disk Management.
Initialising the disk in Disk Management
Right-click on the disk and select Online.
If the disk is marked as offline here, this is likely due to a policy in place on the instance. To fix this, right-click on the disk and select Online.
Then right-click it again and this time select Initialise Disk.
Next, select MBR and click OK.
Initialising the disk with DISKPART
Right-click on the Start Menu button and open Run.
Type cmd and click OK to open the command line application.
At the command prompt, open DISKPART:
C:\> diskpart
Use the following series of DISKPART commands to set the disk to online:
DISKPART> san
SAN Policy : Offline Shared
DISKPART> san policy = OnlineAll
DiskPart successfully changed the SAN policy for the current operating system .
- Implementation of the strategy on the extra disk:
[Code] DISKPART> list disk
Disk ### Status Size Free Dyn Gpt
-------- ------------- ------- ------- --- ---
Disk 0 Online 200 GB 0 B
* Disk 1 Offline 10 GB 1024 KB
DISKPART> select disk 1
Disk 1 is now the selected disk.
DISKPART> attributes disk clear readonly
Disk attributes cleared successfully.
DISKPART> attributes disk
Current Read-only State : No
Read-only : No
Boot Disk : No
Pagefile Disk : No
Hibernation File Disk : No
Crashdump Disk : No
Clustered Disk : No
DISKPART> online disk
DiskPart successfully onlined the selected disk.
Formatting the disk
In Disk Management, right-click on the new disk and select New Simple Volume....
In the wizard, click Next to specify the volume size. It should be set to maximum by default. Click Next to continue.
Leave the new drive letter at default or select a different one, then click Next.
Label the volume (optional) and confirm the formatting options by clicking Next.
In the last window, click Finish to format the disk.
The disk will be available as a drive in File Explorer after the operation.
Detach a volume
If you wish to detach a volume from your instance, the best practice is to unmount the volume in the operating system before detaching it from the instance.
An error message may appear if you have software or processes running on the additional disk. In this case, it is recommended to stop all processes before continuing.
On Linux
Establish an SSH connection to your instance, then use the command below to list the attached disks.
~$ admin@server-1:~$ lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
vda 254:0 0 10G 0 disk
└─vda1 254:1 0 10G 0 part /
vdb 8:0 0 10G 0 disk
└─vdb1 8:1 0 10G 0 part /mnt/disk
Unmount the partition using the command below:
~$ admin@server-1:~$ sudo umount /dev/vdb1
Remove the device ID from the fstab to complete the unmount process, if this is not done, the partition will be mounted right back after a reboot.
~$ admin@server-1:~$ sudo nano /etc/fstab
Save and exit the editor.
Go to the Public Cloud section of your OVHcloud Control Panel and click on Block Storage in the left-hand menu under Storage.
Click on the ... next to the corresponding volume and select Detach from instance.
Click on Confirm in the pop up window to start the process.
On Windows
Establish a remote desktop (RDP) connection to your Windows instance.
Once logged in, right-click on the Start Menu button and open Disk Management.
Right click on the volume you wish to unmount and select Change Drive Letter and Paths....
Click on Remove to remove the drive.
Next, click on Yes to confirm the disk removal.
When finished, you can close the Disk Management window.
Go to the Public Cloud section of your OVHcloud Control Panel and click on Block Storage in the left-hand menu under Storage.
Click on the ... next to the corresponding volume and select Detach from instance.
Click on Confirm in the pop up window to start the process.
Go further
Join our community of users on https://community.ovh.com/en/.
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