Disk Growth — Cloud/VM Expansion

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tags:

• storage
• filesystem
• sysadmin

• linux

  Disk Growth — Cloud/VM Expansion

Disk growth (online disk expansion) is the process of increasing disk, partition, and filesystem sizes on running systems — typically in cloud VMs, hypervisors, or bare-metal servers. This is one of the most common sysadmin operations in cloud environments where storage needs grow dynamically.

The workflow follows a strict layer-by-layer approach: disk → partition → (LVM) → filesystem. Each layer must be expanded in order. Skipping a layer (e.g., trying to resize a filesystem without growing the partition first) will fail.

Key tools / Основные инструменты:

• growpart — automatically grows a partition to fill available space
• resize2fs — resizes ext2/ext3/ext4 filesystems
• xfs_growfs — grows XFS filesystems (grow only, no shrink)
• pvresize / lvextend — LVM physical and logical volume management
• parted — manual partition management

📚 Official Docs / Официальная документация: growpart(1) · resize2fs(8) · xfs_growfs(8) · parted(8)

Partition Growth

Automatic Partition Resize

sudo growpart /dev/sda 1                      # Grow partition №1 / Расширить раздел №1
sudo growpart /dev/vda 1                      # Grow partition (KVM/QEMU) / Расширить раздел (KVM/QEMU)
sudo growpart /dev/nvme0n1 1                  # Grow NVMe partition / Расширить раздел NVMe

Check Before Growth

lsblk                                         # List block devices / Список блочных устройств
df -h                                         # Check filesystem usage / Проверить использование ФС
sudo fdisk -l /dev/sda                        # Check partition table / Проверить таблицу разделов
sudo parted /dev/sda print                    # Alternative check / Альтернативная проверка

Manual Partition Resize (parted)

sudo parted /dev/sda                          # Enter parted / Войти в parted
# (parted) print                              # Show partitions
# (parted) resizepart 1 100%                  # Resize to 100%
# (parted) quit                               # Exit

Install growpart

sudo apt install cloud-guest-utils            # Debian/Ubuntu
sudo dnf install cloud-utils-growpart         # RHEL/Fedora/CentOS
sudo pacman -S cloud-guest-utils              # Arch Linux

Filesystem Expansion

[!CAUTION] Always create a backup or snapshot before resizing a filesystem. Data loss is possible if the operation is interrupted. Всегда создавайте резервную копию или снимок перед изменением размера ФС. Потеря данных возможна при прерывании операции.

EXT2/EXT3/EXT4

sudo resize2fs /dev/sda1                      # Grow EXT4 / Увеличить EXT4
sudo resize2fs /dev/vda1                      # Grow EXT4 (KVM) / Увеличить EXT4 (KVM)
sudo e2fsck -f /dev/sda1                      # Check before resize / Проверить перед изменением
sudo resize2fs /dev/sda1 50G                  # Resize to specific size / Изменить до конкретного размера

XFS

sudo xfs_growfs /mountpoint                   # Grow XFS / Увеличить XFS
sudo xfs_growfs /                             # Grow root XFS / Увеличить корневой XFS
sudo xfs_growfs -d /mnt/data                  # Grow data filesystem / Увеличить ФС данных

[!WARNING] XFS can only be grown (not shrunk) and must be mounted during resize. EXT4 can be shrunk, but only when unmounted. XFS можно только увеличить (не уменьшить) и ФС должна быть смонтирована при изменении. EXT4 можно уменьшить, но только когда размонтирована.

Btrfs

sudo btrfs filesystem resize max /mountpoint  # Grow Btrfs to max / Увеличить Btrfs до максимума
sudo btrfs filesystem resize +10G /mnt        # Grow by 10GB / Увеличить на 10GB
sudo btrfs filesystem resize 1:max /mnt       # Grow device 1 to max / Увеличить устройство 1 до максимума

Check Filesystem Type

df -T                                         # Show filesystem types / Показать типы ФС
lsblk -f                                      # Show filesystems / Показать файловые системы
sudo blkid /dev/sda1                          # Show filesystem UUID and type / Показать UUID и тип ФС

LVM Growth

Extend Physical Volume

sudo pvresize /dev/sda2                       # Resize PV to use full disk / Изменить PV на весь диск
sudo pvs                                      # List PVs / Список PV
sudo pvdisplay /dev/sda2                      # Show PV details / Показать детали PV

Extend Logical Volume

sudo lvextend -l +100%FREE /dev/vg0/lv_root   # Extend to use all free space / Расширить на всё свободное место
sudo lvextend -L +10G /dev/vg0/lv_data        # Extend by 10GB / Расширить на 10GB
sudo lvextend -L 50G /dev/vg0/lv_data         # Extend to 50GB total / Расширить до 50GB всего
sudo lvs                                      # List LVs / Список LV

Resize Filesystem After LVM

sudo lvextend -r -l +100%FREE /dev/vg0/lv_root  # Extend and resize FS / Расширить и изменить ФС
sudo lvextend -L +10G /dev/vg0/lv_root && sudo resize2fs /dev/vg0/lv_root  # EXT4 manual / EXT4 вручную
sudo lvextend -L +10G /dev/vg0/lv_root && sudo xfs_growfs /mount  # XFS manual / XFS вручную

[!TIP] Use lvextend -r to automatically resize the filesystem along with the LV — this is the safest and most convenient method. Используйте lvextend -r для автоматического изменения ФС вместе с LV — это самый безопасный и удобный метод.

Complete LVM Workflow

# 1. Check current state
lsblk
df -h
sudo pvs
sudo vgs
sudo lvs

# 2. Grow partition
sudo growpart /dev/sda 2

# 3. Resize PV
sudo pvresize /dev/sda2

# 4. Extend LV and resize FS
sudo lvextend -r -l +100%FREE /dev/vg0/lv_root

# 5. Verify
df -h

Cloud Providers

AWS EC2

# After resizing EBS volume in AWS Console
lsblk
sudo growpart /dev/xvda 1
sudo resize2fs /dev/xvda1                     # For EXT4 / Для EXT4
sudo xfs_growfs /                             # For XFS / Для XFS

[!NOTE] AWS EBS volume modification can take several minutes. Monitor progress in EC2 console under "Volumes" → "State" column. The volume must be in optimizing or completed state before resizing on the OS level. Модификация тома EBS может занять несколько минут. Следите за прогрессом в консоли EC2.

Google Cloud Platform (GCP)

# After resizing disk in GCP Console
lsblk
sudo growpart /dev/sda 1
sudo resize2fs /dev/sda1                      # For EXT4 / Для EXT4
sudo xfs_growfs /                             # For XFS / Для XFS

Azure

# After resizing disk in Azure Portal
lsblk
sudo growpart /dev/sda 1
sudo resize2fs /dev/sda1                      # For EXT4 / Для EXT4
sudo xfs_growfs /                             # For XFS / Для XFS

[!NOTE] Azure may require stopping and deallocating the VM before resizing the OS disk. Data disks can be resized while the VM is running. Azure может потребовать остановки и деаллокации ВМ перед изменением размера диска ОС.

DigitalOcean

# After resizing droplet
lsblk
sudo growpart /dev/vda 1
sudo resize2fs /dev/vda1                      # For EXT4 / Для EXT4

VMware / Proxmox

# After increasing disk size in hypervisor
lsblk
sudo growpart /dev/sda 1
sudo resize2fs /dev/sda1                      # For EXT4 / Для EXT4
sudo xfs_growfs /                             # For XFS / Для XFS

Troubleshooting

Common Issues

# Check if partition table is GPT or MBR
sudo parted /dev/sda print

# Kernel not recognizing new size
sudo partprobe /dev/sda                       # Reread partition table / Перечитать таблицу разделов
sudo partx -u /dev/sda                        # Update kernel partition table / Обновить таблицу разделов ядра

# LVM not showing full size / LVM
sudo pvscan                                   # Scan for PVs / Сканировать PV
sudo vgscan                                   # Scan for VGs / Сканировать VG
sudo lvscan                                   # Scan for LVs / Сканировать LV

"NOCHANGE" from growpart / growpart

# This means the partition already uses all available space
#
lsblk                                         # Verify disk size vs partition size / Проверить размер диска vs раздела

# If disk was resized but kernel doesn't see it:
#
echo 1 > /sys/class/block/sda/device/rescan   # Rescan SCSI device / Пересканировать SCSI устройство

Verify Growth

# Before
lsblk
df -h

# After partition growth
lsblk

# After filesystem resize
df -h

Filesystem Check

# EXT4 check
sudo e2fsck -f /dev/sda1

# XFS check
sudo xfs_repair /dev/sda1

# Btrfs check
sudo btrfs check /dev/sda1

Real-World Examples

Standard Cloud Growth (EXT4)

# 1. Resize disk in cloud console
# 2. SSH to server / SSH

# 3. Check current state
df -h
lsblk

# 4. Grow partition
sudo growpart /dev/sda 1

# 5. Resize filesystem
sudo resize2fs /dev/sda1

# 6. Verify
df -h

LVM in Production / LVM

# Scenario: Root LV on LVM

# 1. Check state
sudo vgs
sudo lvs
df -h

# 2. Grow partition (if needed)
sudo growpart /dev/sda 2

# 3. Resize PV
sudo pvresize /dev/sda2

# 4. Extend LV with filesystem
sudo lvextend -r -l +100%FREE /dev/mapper/vg0-root

# 5. Verify
df -h
sudo lvs

Add New Disk to LVM

# 1. Identify new disk
lsblk

# 2. Create PV
sudo pvcreate /dev/sdb

# 3. Extend VG
sudo vgextend vg0 /dev/sdb

# 4. Extend LV
sudo lvextend -l +100%FREE /dev/vg0/lv_data

# 5. Resize filesystem
sudo resize2fs /dev/vg0/lv_data              # EXT4
sudo xfs_growfs /mount                        # XFS

Emergency Filesystem Recovery

# Boot into rescue mode

# Unmount filesystem
sudo umount /dev/sda1

# Check and repair
sudo e2fsck -f /dev/sda1                      # EXT4
sudo xfs_repair /dev/sda1                     # XFS

# Resize
sudo resize2fs /dev/sda1                      # EXT4
sudo mount /dev/sda1 /mnt && sudo xfs_growfs /mnt  # XFS

# Remount
sudo mount /dev/sda1 /

Best Practices

[!IMPORTANT]

• Always backup before resizing — snapshots in cloud, LVM snapshots, or full backups.
• Check filesystem integrity before resize with e2fsck -f or xfs_repair.
• Use LVM for flexibility — it allows online resizing without rebooting.
• Take snapshots in cloud before resize — they are your safety net.
• Document growth operations — track disk changes for audit trails.
• Monitor disk usage after resize with df -h.

[!WARNING]

• Never shrink XFS — it does not support shrinking at all.
• Never run e2fsck on a mounted filesystem — it will corrupt data.
• growpart requires free space after the target partition — if another partition follows, you must move or delete it first.

Filesystem Resize Comparison

Typical Growth Workflow

1. Increase disk size in hypervisor/cloud console / Увеличить размер диска в гипервизоре/облаке
2. Rescan (if needed): echo 1 > /sys/class/block/sda/device/rescan
3. growpart to expand partition / расширение раздела
4. pvresize (if LVM) / если LVM
5. lvextend (if LVM) / если LVM
6. resize2fs / xfs_growfs to expand filesystem / расширение ФС
7. df -h to verify / проверка

[!NOTE] Some cloud providers (e.g., GCP) auto-resize the filesystem on reboot. Always verify with df -h. Некоторые облачные провайдеры (например, GCP) автоматически расширяют ФС при перезагрузке. Всегда проверяйте с df -h.

Documentation Links

• growpart: https://manpages.debian.org/testing/cloud-guest-utils/growpart.1.en.html
• resize2fs(8): https://man7.org/linux/man-pages/man8/resize2fs.8.html
• xfs_growfs(8): https://man7.org/linux/man-pages/man8/xfs_growfs.8.html
• parted(8): https://man7.org/linux/man-pages/man8/parted.8.html
• lvextend(8): https://man7.org/linux/man-pages/man8/lvextend.8.html
• pvresize(8): https://man7.org/linux/man-pages/man8/pvresize.8.html
• AWS — Extend EBS Volume: https://docs.aws.amazon.com/ebs/latest/userguide/recognize-expanded-volume-linux.html
• GCP — Resize Disk: https://cloud.google.com/compute/docs/disks/resize-persistent-disk
• Azure — Expand OS Disk: https://learn.microsoft.com/en-us/azure/virtual-machines/linux/expand-disks