---
title: "Increasing the size of an additional disk"
description: "Find out how to increase the size of an additional volume and enlarge its main partition"
url: https://docs.ovhcloud.com/en/guides/public-cloud/compute/increase-the-size-of-an-additional-disk
lang: en
lastUpdated: 2026-02-26
---
# Increasing the size of an additional disk
## Objective
If you have reached the maximum capacity on your additional disk, you can add more storage by increasing its size.
**This guide explains how to increase the size of an additional disk and extend the main partition accordingly.**
## Requirements
- A [Public Cloud instance](https://www.ovhcloud.com/en-gb/public-cloud/) in your Public Cloud project
- An [additional disk](/en/guides/public-cloud/compute/create-and-configure-an-additional-disk-on-an-instance.md) created in your project
- Administrative (sudo) access to your instance via SSH (Linux) or RDP (Windows)
***
### OVHcloud Control Panel Access
- **Direct link:** Public Cloud Projects
- **Navigation path:** Public Cloud > Select your project
***
## Instructions
The following steps presume that you have configured an additional disk according to [our guide](/en/guides/public-cloud/compute/create-and-configure-an-additional-disk-on-an-instance.md).
## Monitoring disk usage before resizing
:::warning
We recommend that you always maintain 20% free space on your storage volumes. This ensures optimum performance and avoids the risk of system degradation or failure when the volume reaches its maximum capacity.
:::
To ensure that you resize your disk at the right moment, it is essential to monitor disk usage regularly. Below are quick tutorials for both Windows and Linux to help you track disk space and anticipate when an upgrade is needed.
**On Windows**
Using Command Prompt
Open Command Prompt (Win + R → cmd → Enter).
Run the following command:
```bash
wmic logicaldisk get name, size, freespace
```
This will display the free space and total size of each disk.
Using PowerShell
Open PowerShell as Administrator.
Run the following command:
```bash
Get-PSDrive | Where-Object {$_.Free -ne $null} | Select-Object Name, Used, Free
```
This will show the used and available disk space.
**On Linux**
Using 'df' command
To check overall disk usage, run:
```bash
df -h
```
This will display disk usage in a human-readable format.
Using 'lsblk' command
To view disk partitions and their sizes:
```bash
lsblk
```
### Modifying the size of the disk
Click on `Block Storage
` in the left-hand menu under **Storage & backup**
.
If the volume is attached to a **Windows instance**
, click on `...
` in the row of the volume and select `Detach from instance
`.
Click on `...
` in the row of the volume and select `Edit
`.
In the popup window, enter the new size for the volume and click on `Modify the volume
`.
### Extending the partition (Linux instance)
Establish an SSH connection to your instance in order to adjust the partition to the resized disk.
Unmount the disk first by using this command:
```bash
admin@server:~$ sudo umount /mnt/disk
```
Recreate the partition:
```bash
admin@server:~$ sudo fdisk /dev/vdb
```
```console
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
```
```console
Command (m for help): d
Selected partition 1
Partition 1 has been deleted.
```
```console
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 (2048-146800639, default 2048):
Last sector, +sectors or +size{K,M,G,T,P} (2048-146800639, default 146800639):
Created a new partition 1 of type 'Linux' and of size 70 GiB.
```
```console
Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.
```
Verify and check the partition:
```bash
admin@server:~$ sudo e2fsck -f /dev/vdb1
e2fsck 1.42.12 (29-Aug-2014)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/vdb: 12/3276800 files (0.0% non-contiguous), 251700/13107200 blocks
```
```bash
admin@server:~$ sudo resize2fs /dev/vdb1
resize2fs 1.42.12 (29-Aug-2014)
Resizing the filesystem on /dev/vdb to 18350080 (4k) blocks.
The filesystem on /dev/vdb is now 18350080 (4k) blocks long.
```
Finally, re-mount and check the disk:
```bash
admin@server:~$ sudo mount /dev/vdb1 /mnt/disk/
```
```bash
admin@server:~$ 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 69G 52M 66G 1% /mnt/disk
```
Once this is completed, detach the volume from the instance and reattach it to ensure the updated QoS settings (IOPS and bandwidth) are properly applied.
### Extending the partition (Windows instance)
Before proceeding, reattach the volume to the instance. Click on `...
` in the row of the volume and select `Attach to instance
`.
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 extended disk now displays the additional capacity as unallocated space.
Right-click on the volume and select `Extend Volume
` from the context menu.
In the "Extend Volume Wizard", click on `Next
` to proceed.
You can modify the disk space in this step if you want to add less than the entire amount to the partition. Click on `Next
`.
Click on `Finish
` to complete the process.
The resized volume now includes the additional disk space.
Once this is completed, detach the volume from the instance and reattach it to ensure the updated QoS settings (IOPS and bandwidth) are properly applied.
## Go further
[Creating and configuring an additional disk on an instance](/en/guides/public-cloud/compute/create-and-configure-an-additional-disk-on-an-instance.md)
[Change your Block Storage volume type](/en/guides/public-cloud/compute/switch-volume-type.md)
Join our [community of users](https://community.ovhcloud.com/).