Clonezilla

Open-source disk imaging and cloning tool for bare-metal backup, mass deployment, and disaster recovery.

Table of Contents#

Overview
Editions and Downloads
Booting Clonezilla Live
MBR vs GPT Considerations
Creating a Disk Image (Interactive)
Restoring a Disk Image (Interactive)
Device-to-Device Cloning
Command-Line Usage
Clonezilla SE and DRBL Setup
Backup Verification
Advanced Features
Troubleshooting
See Also
Sources

1. Overview#

Clonezilla is a partition and disk imaging/cloning tool similar to commercial products like Norton Ghost or Acronis True Image. It clones only the used blocks of a filesystem, making images smaller and faster to create than raw disk copies. Clonezilla supports a wide range of filesystems including ext2/3/4, XFS, Btrfs, NTFS, FAT, HFS+, and more.

Key features:

Block-level imaging - clones only used blocks, reducing image size and time
Filesystem awareness - supports ext2/3/4, XFS, Btrfs, NTFS, FAT12/16/32, HFS+, UFS, VMFS, and others
Flexible storage - images can be saved to local disks, SSH/SFTP servers, Samba shares, NFS, or WebDAV
Multicast deployment - Clonezilla SE can image dozens of machines simultaneously via PXE/DRBL
Encryption and compression - supports image encryption and multiple compression levels
MBR and GPT - handles both legacy BIOS and UEFI partition schemes

2. Editions and Downloads#

Edition	Use Case	PXE Support
Clonezilla Live	Single-machine backup and restore	No (boot from USB/CD)
Clonezilla SE (Server Edition)	Mass deployment to many machines	Yes (via DRBL)

Download from clonezilla.org/downloads.php. Available as ISO (for CD/DVD) or zip (for USB).

Creating a Bootable USB#

# Using dd (replace <device> with your USB device, e.g., /dev/sdb)
sudo dd if=clonezilla-live-<version>.iso of=/dev/<device> bs=4M status=progress
sync

Alternatively, use tools like Ventoy, Rufus (Windows), or Etcher.

3. Booting Clonezilla Live#

Insert the bootable USB or CD/DVD.
Boot the target machine and select the Clonezilla media from the boot menu (often F12, F2, or Esc at POST).
Select a language, keyboard layout, and then Start Clonezilla.
Choose the operation mode: device-image or device-device.

4. MBR vs GPT Considerations#

Understanding the partition table type is critical before imaging or restoring.

Aspect	MBR (Master Boot Record)	GPT (GUID Partition Table)
Max disk size	2 TB	9.4 ZB (effectively unlimited)
Max partitions	4 primary (or 3 primary + 1 extended)	128 (default)
Boot mode	Legacy BIOS	UEFI (can also work with BIOS via protective MBR)
Partition ID	Byte codes (e.g., 0x83 for Linux)	GUIDs (e.g., `0FC63DAF-...` for Linux filesystem)

Important notes:

When restoring an image, the target disk's partition table type should match the source. Clonezilla preserves the partition table in the image.
Restoring a GPT image to a smaller disk may fail if partitions exceed the target size. Use -k1 (proportional resize) to handle size differences.
UEFI systems require an EFI System Partition (ESP) with a FAT32 filesystem and GPT layout.
To check partition table type before imaging: sudo fdisk -l /dev/<device> or sudo parted /dev/<device> print.

5. Creating a Disk Image (Interactive)#

Boot Clonezilla Live and select Start Clonezilla.
Choose device-image.
Select the image repository location (local disk, SSH server, Samba share, NFS, etc.).
Choose Beginner or Expert mode.
Select savedisk (full disk) or saveparts (specific partitions).
Name the image and select the source disk/partitions.
Choose compression level and whether to check/repair the filesystem before imaging.
Confirm and wait for the process to complete.

6. Restoring a Disk Image (Interactive)#

Boot Clonezilla Live and select Start Clonezilla.
Choose device-image.
Connect to the image repository.
Choose Beginner or Expert mode.
Select restoredisk or restoreparts.
Select the image and the target disk/partition.
Confirm the operation (target will be overwritten).

7. Device-to-Device Cloning#

Boot Clonezilla Live and select device-device mode.
Choose Beginner or Expert mode.
Select disk_to_local_disk or part_to_local_part.
Choose the source and target devices.
Confirm and start the cloning process.

For cloning to a smaller disk, use Expert mode and enable -k1 (proportional partition resizing) or -k2 (use partition table from image, skip geometry check).

8. Command-Line Usage#

Clonezilla can be run non-interactively for scripting and automation. The main tool is ocs-sr (Opensource Clone System - System Rescue).

Save a Disk Image#

/usr/sbin/ocs-sr -q2 -c -j2 -z5p -i 4096 -sfsck -senc -p poweroff savedisk <image-name> <device>

Key flags:

Flag	Description
`-q2`	Use partclone (default, fastest)
`-c`	Client waits for confirmation before starting
`-j2`	Clone hidden data between MBR and first partition
`-z5p`	Use zstd parallel compression
`-z1p`	Use gzip parallel compression
`-z0`	No compression
`-i 4096`	Split image into 4096 MB chunks
`-sfsck`	Skip filesystem check before saving
`-senc`	Skip encryption
`-p poweroff`	Poweroff after completion (`reboot`, `true` for prompt)
`-k1`	Proportional partition resize on restore

Restore a Disk Image#

/usr/sbin/ocs-sr -g auto -e1 auto -e2 -r -j2 -c -p reboot restoredisk <image-name> <device>

Clone Disk to Disk#

/usr/sbin/ocs-onthefly -g auto -e1 auto -e2 -r -j2 -sfsck -k1 -pa poweroff -f <source> -d <target>

Batch Mode (No Prompts)#

/usr/sbin/ocs-sr -batch -q2 -j2 -z5p -p true savedisk my-image sda

9. Clonezilla SE and DRBL Setup#

Clonezilla Server Edition (SE) uses DRBL (Diskless Remote Boot in Linux) for PXE-based mass deployment.

Install DRBL#

# Debian/Ubuntu
sudo apt install drbl

# Configure DRBL (interactive)
sudo drblsrv -i

# Set up DRBL for the network
sudo drblpush -i

Start Clonezilla SE Multicast Session#

sudo drbl-ocs -b -g auto -e1 auto -e2 -r -x -j2 -sc0 -p true \
  --clients-to-wait <count> --max-time-to-wait 300 \
  -l en_US.UTF-8 startdisk multicast_restore <image-name> <device>

Key parameters:

Parameter	Description
`--clients-to-wait <count>`	Number of client machines to wait for before starting
`--max-time-to-wait <seconds>`	Maximum seconds to wait for clients
`startdisk`	Operate on whole disks
`multicast_restore`	Use multicast mode for simultaneous restore

Network Requirements#

DRBL server needs two NICs: one for internet, one for the client network
DHCP and TFTP services are configured by drblpush
All client machines must support PXE boot
A dedicated switch/VLAN for the deployment network is recommended to avoid DHCP conflicts

10. Backup Verification#

Verify Image Integrity#

Clonezilla can check saved images for corruption:

/usr/sbin/ocs-chkimg <image-name>

This verifies all partclone image files in the image directory against their stored checksums.

Verify During Save#

Use Expert mode and enable Check the saved image after saving. This adds time but confirms the image is valid immediately.

Manual Verification#

# Check individual partclone image files
partclone.chkimg -s /path/to/image/<partition>.img.zst

# List image contents
cat /path/to/image/clonezilla-img
cat /path/to/image/dev-fs.list
cat /path/to/image/parts

Test Restore#

The safest verification is a test restore to a spare disk or virtual machine. In a VM:

Create a VM with a disk at least as large as the original.
Attach the Clonezilla ISO and the image storage.
Restore the image and verify the system boots.

11. Advanced Features#

Encryption#

In Expert mode, select the option to encrypt the image. Clonezilla uses ecryptfs for encryption:

# Save with encryption
/usr/sbin/ocs-sr -q2 -j2 -z5p -enc -p true savedisk my-encrypted-image sda

Custom Post-Clone Scripts#

Clonezilla supports running scripts after cloning, useful for hostname changes, driver injection, or configuration:

# Place scripts in the image directory as custom-ocs
# They run automatically after restore

Image Conversion#

Convert between formats:

# Convert a savedisk image to a smaller format
ocs-cvtimg-comp -b -z5p <image-name>

Troubleshooting#

Issue	Cause	Solution
Image restore fails on smaller disk	Partitions exceed target capacity	Use Expert mode with `-k1` flag for proportional resize
UEFI system won't boot after restore	EFI boot entry not updated	Boot Clonezilla, mount ESP, run `efibootmgr` to recreate entries
Image save fails midway	Insufficient space on repository	Use `-i 4096` to split image; check destination free space
Cannot find disk in Clonezilla	Hardware RAID or NVMe driver missing	Load appropriate kernel modules; use `lsblk` to verify device visibility
Multicast session never starts	Clients not PXE booting	Verify DHCP/TFTP on DRBL server; check network and BIOS boot order
Corrupt image detected	Disk errors during save, bad storage	Re-save the image; run `ocs-chkimg` to confirm; use `-fsck` flag
GPT image restored to MBR disk	Partition table mismatch	Ensure target uses GPT; use `gdisk` to convert if needed