Repartitioning a VPS after a storage upgrade

This guide explains how to increase your storage space after a disk upgrade.

After upgrading the storage capacity of your VPS, you will need to repartition the disk space to take advantage of the full size. The following steps outline the procedure.

Requirements

• Administrative access to your VPS (Windows)
• Rescue mode activated on the VPS (Linux only)

Instructions

After a memory (RAM) or processor (vCores) upgrade, these resources of your VPS are automatically adjusted. The usable disk space, however, is not automatically increased when you upgrade the storage of your VPS.

Linux

Back up your data

Attempting to extend a partition can lead to data loss. It is therefore strongly recommended that you back up the data on your VPS.

Activate rescue mode and verify the partitions

If the VPS is not already in rescue mode, activate it by using our guide.

You can then verify the configuration of the disks:

lsblk

The partition corresponding to rescue mode (sda1 in this example) is mounted in the directory /, and the disk of the VPS is named sdb and should have no mount point.

Example:

NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 254:0 0 10G 0 disk
└─sda1 254:1 0 10G 0 part /
sdb 254:16 0 25G 0 disk
└─sdb1 254:17 0 25G 0 part

If your result looks similar to the output above and the column MOUNTPOINT is empty in the corresponding line, you can proceed with the next step.

However, if your result shows that there is a mount point for the VPS partition, it needs to be unmounted first.

Example:

sdb 254:16 0 25G 0 disk
└─sdb1 254:17 0 25G 0 part /mnt/sdb1

In the example output above, the partition sdb1 is mounted at /mnt/. To resize the partition, this partition must not be mounted.

To unmount your partition, use the following command:

umount /dev/partition_name

In this example configuration, the command would be:

umount /dev/sdb1

Check the filesystem

Before you proceed, it is recommended to check the filesystem to see if there are errors in the partition. The command is as follows:

e2fsck -yf /dev/sdb1

e2fsck 1.42.9 (4-Feb-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/sdb1: 37870/1310720 files (0.2% non-contiguous), 313949/5242462 blocks

If you see any errors, take note of them and resolve them as required. Below is a (non-exhaustive) list of the most common errors you might see:

• bad magic number in superblock: Do not continue. Please read and follow our instructions on How to fix a bad magic number in superblock error.
• /dev/vdb1 has unsupported feature(s): metadata_csum followed by e2fsck: Get a newer version of e2fsck!: Update e2fsck. If the latest version is not available via apt (or another package manager), you will need to compile it from source.

Launch the fdisk application

If the filesystem check is completed successfully, launch the fdisk application. In the settings, you need to enter the name of the disk and not the name of the partition. For example, if your partition is sdb1, the disk name will be /dev/sdb.

fdisk -u /dev/sdb

Delete the old partition

Before deleting the old partition, it is recommended that you write down the number corresponding to the first sector of the partition. You can find this information through the command p. The information is listed under the Start field. Save this data for later.

Command (m for help): p

Disk /dev/sdb: 21.5 GB, 21474836480 bytes
54 heads, 49 sectors/track, 15851 cylinders, total 41943040 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000132ff

Device Boot Start End Blocks Id System
/dev/sdb1 * *2048* 41941745 20969849 83 Linux

Then delete the partition with the command d.

Command (m for help): d
Selected partition 1

The single partition will automatically be deleted.

Create a new partition

You now need to create a new partition with the command n. It is recommended that you use the default values.

Command (m for help): n
Partition type:
p primary (0 primary, 0 extended, 4 free)
e extended
Select (default p): p
Partition number (1-4, default 1): 1
First sector (2048-41943039, default 2048): 2048
Last sector, +sectors or +size{K,M,G} (2048-41943039, default 41943039): 41943039.

On the First sector line, check that the default value is the same as the one you have previously written down. If it is different, use the value you have written down.

If you see the following message:

Partition #1 contains a ext4 signature.

Do you want to remove the signature? [Y]es/[N]o:

Enter n and proceed.

Answering y would mean overwriting the existing ext4 file system on Partition 1 and agreeing to destroy the data on it.

Make the partition bootable

You now need to ensure that the partition is bootable. You can do this using the command a.

Command (m for help): a

Partition number (1-4): 1

Save your changes and exit the application with the command w:

Command (m for help): w

The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.

Extend the filesystem on the partition

The partition has been extended, but the filesystem still occupies the same space as before. To extend it, simply enter the following command:

resize2fs /dev/sdb1

resize2fs 1.42.9 (4-Feb-2014)
Resizing the filesystem on /dev/sdb1 to 5242624 (4k) blocks.
The filesystem on /dev/sdb1 is now 5242624 blocks long.

Check the results

To check if the extension has been successful, you can mount the newly created partition and verify its size.

mount /dev/sdb1 /mnt

df -h

Filesystem Size Used Avail Use% Mounted on
/dev/sda1 991M 793M 132M 86% /
none 4.0K 0 4.0K 0% /sys/fs/cgroup
udev 1.9G 12K 1.9G 1% /dev
tmpfs 386M 360K 386M 1% /run
none 5.0M 0 5.0M 0% /run/lock
none 1.9G 0 1.9G 0% /run/shm
none 100M 0 100M 0% /run/user
/dev/sdb1 50G 842M 48G 2% /mnt

You will find the new partition size listed below the label size.

How to fix a bad magic number in superblock error

If the command e2fsck returns the error message bad magic number in superblock, you should check and repair the filesystem by using a backup of the superblock. To see which backups of the superblock are available, enter the following command:

dumpe2fs /dev/sdb1 | grep superblock

Primary superblock at 0, Group descriptors at 1-6
Backup superblock at 32768, Group descriptors at 32769-32774
Backup superblock at 98304, Group descriptors at 98305-98310
Backup superblock at 163840, Group descriptors at 163841-163846
Backup superblock at 229376, Group descriptors at 229377-229382
Backup superblock at 294912, Group descriptors at 294913-294918
Backup superblock at 819200, Group descriptors at 819201-819206
Backup superblock at 884736, Group descriptors at 884737-884742
Backup superblock at 1605632, Group descriptors at 1605633-1605638
Backup superblock at 2654208, Group descriptors at 2654209-2654214
Backup superblock at 4096000, Group descriptors at 4096001-4096006
Backup superblock at 7962624, Group descriptors at 7962625-7962630
Backup superblock at 11239424, Group descriptors at 11239425-11239430
Backup superblock at 20480000, Group descriptors at 20480001-20480006
Backup superblock at 23887872, Group descriptors at 23887873-23887878

Then use the first superblock backup to check and repair the filesystem:

fsck -b 32768 /dev/sdb1

Windows

Access File and Storage Services

You can find this in the Server Manager:

Resize the volume

Right-click on the C: volume and select Extend Volume....

You will then be prompted to choose your new volume size:

Enter your desired size and click OK. Your volume will now be extended.

Go further

For more information and tutorials, please see our other VPS support guides or explore the guides for other OVHcloud products and services.