A disk upgrade increases the virtual disk size. Linux may still show the old usable space until you expand the partition and filesystem.
Make a current off-server backup before changing partitions or filesystems. The examples cover ext4 and XFS on a single disk, with or without a simple LVM layout. They do not cover RAID, encrypted volumes or moving partitions.
1. Check the disk and filesystem
Follow the upgrade’s power-cycle instructions and keep the VNC console open. Run:
Check that the whole disk shows the upgraded capacity. Then identify the root filesystem:
2. Expand a partition into adjacent free space
Install growpart if it is missing:
Debian / Ubuntu
Rocky / AlmaLinux
/dev/vda. Use the disk and partition number from your own layout. Preview the change first:
Proceed only if it keeps the partition start unchanged and extends the intended partition into adjacent free space:
If the partition already fills the disk, it does not need this step. If Linux cannot reread the partition table, arrange a clean reboot and inspect the result before continuing; do not force repeated writes.
3. Expand the filesystem
Plain ext4
Plain XFS
LVM with ext4 or XFS
For an ext4 root filesystem directly on /dev/vda1:Use the actual filesystem device. Do not run this command on XFS or on an LVM physical volume. XFS grows using its mounted directory. For the root filesystem:The underlying partition must already have the extra space. XFS cannot be shrunk with this command. Inspect the volume names and free space:If the physical volume is inside a partition, grow that partition first using its actual number. For example, /dev/vda3 requires growpart -N /dev/vda 3, followed by growpart /dev/vda 3 after checking the preview.Let LVM recognise the larger physical volume:Substitute your actual physical volume. If the volume group already has enough free space, a partition change and pvresize are unnecessary.Extend the root logical volume by an amount no greater than the group’s free space. This example adds 10 GiB; replace both the amount and logical-volume path:Then grow the filesystem: for ext4, run sudo resize2fs /dev/VG/ROOT_LV; for XFS mounted at /, run sudo xfs_growfs /. Do not allocate space to a different logical volume by guessing its name. 4. Verify the result
df should show the larger usable filesystem. Check that your applications work and that the system logs contain no storage errors.
If another partition is in the way
Do not delete swap, EFI or recovery partitions just to make growpart succeed. Moving partitions requires a separate maintenance and recovery plan. The Linux rescue guide explains how to inspect the disk and recover files; booting rescue media alone does not make a partition move safe.
For a layout you cannot safely extend, consider moving your data to a freshly installed VPS with the required disk size, then verifying the new installation before cancelling the old one. 
