Expanding disk space after growing a disk (ext4, xfs, LVM)

1. Why are there two stages?

Growing a disk is a two-stage job:

1. Panel (or API/CLI): increases the size of the virtual disk. The server sees the new size immediately, but the partition and file system inside stay at the old size.
2. Inside the server (this guide): you expand the partition, LVM if used, and the file system to the new size.

An HDD (large storage) additional disk is grown with exactly the same steps.

Good news: expansion is done while the server is running (online); you do not need to shut down or unmount. Shrinking is not possible; you can only grow.

2. First, check the situation

After growing in the panel, look at your disk layout on the server:

lsblk -o NAME,SIZE,TYPE,FSTYPE,MOUNTPOINT
df -hT

lsblk shows the disk's new size. The layout below it will be one of three kinds:

If lsblk still shows the old size, have the server rescan the disk (replace X with the disk name, e.g. sdb):

echo 1 > /sys/class/block/sdX/device/rescan
lsblk

3. Expanding the space

3.1 Partitioned disk (sdb1)

Grow the partition first, then the file system:

growpart /dev/sdb 1          # grows partition 1 of disk sdb to the end of the disk
resize2fs /dev/sdb1          # if ext4
# if xfs, use instead: xfs_growfs /mnt/data     (give the mounted folder)
df -h /mnt/data

If growpart is missing, install cloud-guest-utils (Ubuntu/Debian: apt install cloud-guest-utils) or cloud-utils-growpart (AlmaLinux/Rocky: dnf install cloud-utils-growpart). If growpart says "NOCHANGE: partition ... cannot be grown", the partition already reaches the end of the disk; go straight to the file system command.

3.2 Unpartitioned disk (formatted directly)

With no partition only the file system command is needed:

resize2fs /dev/sdb           # if ext4
xfs_growfs /mnt/data         # if xfs (mounted folder)
df -h /mnt/data

3.3 If you use LVM

Expand the physical volume first, then the logical volume (-r grows the file system too):

pvresize /dev/sdc
lvextend -r -l +100%FREE /dev/vgdata/lvdata    # take the vg and lv names from your system
df -h /mnt/lvm

If you do not know the names run vgs and lvs. If the disk is partitioned (LVM sits on sdc1), first run growpart /dev/sdc 1, then pvresize /dev/sdc1.

4. Growing the root disk

When you upgrade your plan on Gyro Cloud Istanbul, the root disk grows too (disks only grow, never shrink). In most cases the server expands it automatically: when we tested Ubuntu 24.04 and AlmaLinux 9 servers, lsblk and df -h showed the new size right away and no manual command was needed. Still, check:

df -h /

If / does not show the new size, expand it by hand. Find the root partition number with lsblk (e.g. sda1 on Ubuntu, sda4 on AlmaLinux):

growpart /dev/sda 1          # for AlmaLinux/Rocky usually: growpart /dev/sda 4
resize2fs /dev/sda1          # ext4 (Ubuntu/Debian); use your own root partition number
xfs_growfs /                 # xfs (AlmaLinux/Rocky)
df -h /

5. Common problems

I grew the disk but the space is the same. df -h shows the size of the file system, not the disk; lsblk shows the disk size. Compare the two: if lsblk shows the new size, the missing piece is the command in Section 3. If lsblk also shows the old size, run echo 1 > /sys/class/block/sdX/device/rescan, and if that does not help check in the panel that the grow task finished.

The panel says "delete snapshots" and does not grow. A disk cannot be grown while the server has a snapshot. Delete the snapshot, grow the disk, take a new snapshot if needed.

resize2fs: Bad magic number in super-block error. The file system is not ext4 (probably xfs). Check the type with df -hT and use xfs_growfs.

xfs_growfs: ... is not a mounted XFS filesystem error. Give xfs_growfs the mounted folder, not the device (e.g. xfs_growfs /mnt/data).

I want to shrink the disk. Additional and root disks cannot be shrunk. If you need a smaller space, add a new small disk (using a disk guide), move the data and delete the old one. Before deleting, run umount and remove the fstab line.

I reinstalled the operating system; my additional disk is gone. A reinstall deletes additional disks and resets the root disk. Back up important data beforehand.

Do I need to reboot after expanding? No. Expansion is done online.

6. Frequently asked questions