Disk cloning

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Disk cloning is the process of duplicating all data on a digital storage drive, such as a hard disk or solid state drive, using hardware or software techniques. [1] Unlike file copying, disk cloning also duplicates the filesystems, partitions, drive meta data and slack space on the drive. [2] Common reasons for cloning a drive include; data backup and recovery; duplicating a computer's configuration for mass deployment and for preserving data for digital forensics purposes. [1] [3] [4] Drive cloning can be used in conjunction with drive imaging where the cloned data is saved to one or more files on another drive rather than copied directly to another drive.

Contents

Background

Figure 1: An illustration of connecting two drives to a computer to clone one drive (the source drive) to another (the destination) drive. Cloning Hard disk drive.jpg
Figure 1: An illustration of connecting two drives to a computer to clone one drive (the source drive) to another (the destination) drive.

Disk cloning occurs by copying the contents of a drive called the source drive. While called "disk cloning", any type of storage medium that connects to the computer via USB, NVMe or SATA can be cloned. A small amount of data is read and then held in the computer's memory. The data is then either written directly to another (destination) drive or to a disk image.

Typically, the destination drive is connected to a computer (Fig. 1). Once connected, a disk cloner is used to perform the clone itself. A hardware-based drive cloner can be used which does not require a computer. [5] However, software cloners tend to allow for greater flexibility because they can exclude unwanted data from being duplicated reducing cloning time. For example, the filesystem and partitions can be resized by the software allowing data to be cloned to a drive equal to or greater than the total used space. Most hardware-based cloners typically require for the destination drive to be the same size as the source drive even if only a fraction of the space is used. [5] Some hardware cloners can clone only the used space but tend to be much more expensive.

Applications

Deployment

A common use of disk cloning is for deployment. For example, a group of computers with similar hardware can be set up much quicker by cloning the configuration. In educational institutions, students are typically expected to experiment with computers to learn. Disk cloning can be used to help keep computers clean and configured correctly. [6] Further, while installing the operating system is quick, installation of programs and ensuring a consistent configuration is time consuming. Thus, disk cloning seeks to mitigate this administrative challenge.

Digital forensics

One of the most common applications of disk cloning is for digital forensics purposes. [7] This aims to ensure that data is preserved at the time it was acquired for later analysis. [8] Techniques for cloning a disk for forensic purposes differ from cloning a drive for other purposes. Typically, the cloning process itself must not interfere with the data. Because software cannot be installed on the system, a hardware-based cloner is generally used to duplicate the data to another drive or image. [1] Further, the hardware-based cloner also has write-blocking capabilities which intercepts write commands to prevent data being written to the drive. [8]

Backup

Disk cloning can be used as a backup solution by creating a duplicate of data as it existed when the clone was started. [9] The clone can be used to restore corrupted files such as corrupted databases. In modern software solutions, it is not uncommon for disk cloning techniques to be combined with disk imaging techniques to create a backup solution.

Drive upgrade

Upgrading to a larger or faster drive can be facilitated by cloning the old drive to the new drive once it is installed into the system. This reduces the need to having to manually reinstall applications, drivers and the operating system. [10] The procedure can be used when migrating from mechanical hard disk drives to solid state drives. [11] Modern cloning software tends to communicate with storage devices through a common interface, which means, that any storage device can be cloned and migrated. Sometimes, booting from the destination drive can fail and require adjustments in the computer's UEFI or BIOS to make the new clone bootable. [12]

Technical challenges

There are several technical challenges that need to be considered when planning to clone a drive.

Drive in use

Often, cloning software runs within the operating system which is running off of one of the drives being cloned. As a result, any attempt to clone the contents of the drive, even to a file, would result in data corruption. Consequently, the drive cloner must ensure that the data on the source drive remains in a consistent state at the time of reading. Further, in the case, that the user desires to clone to the computer's system drive, this generally cannot be done while the operating system is running.

A common solution to cloning a drive that is in use, which is utilized by software such as CloneZilla, is to boot from a Linux-based operating system so the drive can be copied and/or overwritten. [6] [13] This approach is not suitable for servers that need to be running all the time and cannot be shutdown routinely to perform the backup (or cloning) operation. [14] Further, the Linux-based operating system must provide appropriate drivers for the system's hardware. Drivers are also required for the source and destination drives and for any attached storage involved in facilitating the cloning operation such as USB, tape device and networking drivers.

Some server-based operating system incorporate mechanisms to allow the drive to be safely backed up while the system is running to overcome these challenges. For example, Windows Server 2003 (and later) includes volume shadow service (VSS). [14] [15] VSS takes a snapshot of the drive so that any changes are not written to the snapshot. [16] The snapshot creates a virtual drive called a shadow volume that is backed up (or cloned) by the software.

Slow

Disk cloning can be time consuming, especially, for large disks because a true clone needs to copy all the data on the disk even if most data resides in unallocated drive space. [1] Software solutions can determine the space in use and only copy the used data reducing the time needed to clone the drive. Some drive cloners make use of multithreading to further speed up the cloning operation. [1]

See also

Related Research Articles

A disk image is a snapshot of a storage device's structure and data typically stored in one or more computer files on another storage device. Traditionally, disk images were bit-by-bit copies of every sector on a hard disk often created for digital forensic purposes, but it is now common to only copy allocated data to reduce storage space. Compression and deduplication are commonly used to reduce the size of the image file set. Disk imaging is done for a variety of purposes including digital forensics, cloud computing, system administration, as part of a backup strategy, and legacy emulation as part of a digital preservation strategy. Disk images can be made in a variety of formats depending on the purpose. Virtual disk images are intended to be used for cloud computing, ISO images are intended to emulate optical media and raw disk images are used for forensic purposes. Proprietary formats are typically used by disk imaging software. Despite the benefits of disk imaging the storage costs can be high, management can be difficult and they can be time consuming to create.

<span class="mw-page-title-main">Live CD</span> Complete, bootable computer installation that runs directly from a CD-ROM

A live CD is a complete bootable computer installation including operating system which runs directly from a CD-ROM or similar storage device into a computer's memory, rather than loading from a hard disk drive. A live CD allows users to run an operating system for any purpose without installing it or making any changes to the computer's configuration. Live CDs can run on a computer without secondary storage, such as a hard disk drive, or with a corrupted hard disk drive or file system, allowing data recovery.

<span class="mw-page-title-main">USB flash drive</span> Data storage device

A USB flash drive is a data storage device that includes flash memory with an integrated USB interface. It is typically removable, rewritable and much smaller than an optical disc. Most weigh less than 30 g (1 oz). Since first appearing on the market in late 2000, as with virtually all other computer memory devices, storage capacities have risen while prices have dropped. As of March 2016, flash drives with anywhere from 8 to 256 gigabytes (GB) were frequently sold, while 512 GB and 1 terabyte (TB) units were less frequent. As of 2023, 2 TB flash drives were the largest currently in production. Some allow up to 100,000 write/erase cycles, depending on the exact type of memory chip used, and are thought to physically last between 10 and 100 years under normal circumstances.

In information technology, a backup, or data backup is a copy of computer data taken and stored elsewhere so that it may be used to restore the original after a data loss event. The verb form, referring to the process of doing so, is "back up", whereas the noun and adjective form is "backup". Backups can be used to recover data after its loss from data deletion or corruption, or to recover data from an earlier time.  Backups provide a simple form of disaster recovery; however not all backup systems are able to reconstitute a computer system or other complex configuration such as a computer cluster, active directory server, or database server.

<span class="mw-page-title-main">Ghost (disk utility)</span> Disk cloning and backup tool

GHOST, now Symantec™ GHOST Solution Suite (GSS)for enterprise, is a disk cloning and backup tool originally developed by Murray Haszard in 1995 for Binary Research. The technology was acquired in 1998 by Symantec.

In computing, a clone is hardware or software that is designed to function in exactly the same way as another system. A specific subset of clones are remakes, which are revivals of old, obsolete, or discontinued products.

Bare-metal restore is a technique in the field of data recovery and restoration where the backed up data is available in a form that allows one to restore a computer system from "bare metal", i.e. without any requirements as to previously installed software or operating system.

A boot image is a type of disk image. When it is transferred onto a boot device it allows the associated hardware to boot.

Data loss is an error condition in information systems in which information is destroyed by failures or neglect in storage, transmission, or processing. Information systems implement backup and disaster recovery equipment and processes to prevent data loss or restore lost data. Data loss can also occur if the physical medium containing the data is lost or stolen.

In computing, data recovery is a process of retrieving deleted, inaccessible, lost, corrupted, damaged, or formatted data from secondary storage, removable media or files, when the data stored in them cannot be accessed in a usual way. The data is most often salvaged from storage media such as internal or external hard disk drives (HDDs), solid-state drives (SSDs), USB flash drives, magnetic tapes, CDs, DVDs, RAID subsystems, and other electronic devices. Recovery may be required due to physical damage to the storage devices or logical damage to the file system that prevents it from being mounted by the host operating system (OS).

<span class="mw-page-title-main">Recovery disc</span> Media intended to restore the operating system

The terms Recovery disc, Rescue Disk/Disc and Emergency Disk all refer to a capability to boot from an external device, possibly a thumb drive, that includes a self-running operating system: the ability to be a boot disk/Disc that runs independent of an internal hard drive that may be failing, or for some other reason is not the operating system to be run.

<span class="mw-page-title-main">Acronis Cyber Protect Home Office</span> Data protection software for personal users

Acronis Cyber Protect Home Office is a software package produced by Acronis International GmbH that aims to protect the system from ransomware and allows users to backup and restore files or entire systems from a backup archive, which was previously created using the software. Since 2020, Acronis Cyber Protect Home Office includes malware and Zoom protection. The software is used by technicians to deploy operating systems to computers and by academics to help restore computers following analysis of how viruses infect computers.

<span class="mw-page-title-main">Computer repair technician</span> Person who repairs and maintains computers and servers

A computer repair technician is a person who repairs and maintains computers and servers. The technician's responsibilities may extend to include building or configuring new hardware, installing and updating software packages, and creating and maintaining computer networks.

Disk encryption is a technology which protects information by converting it into code that cannot be deciphered easily by unauthorized people or processes. Disk encryption uses disk encryption software or hardware to encrypt every bit of data that goes on a disk or disk volume. It is used to prevent unauthorized access to data storage.

<span class="mw-page-title-main">Computer appliance</span> Dedicated computer system

A computer appliance is a computer system with a combination of hardware, software, or firmware that is specifically designed to provide a particular computing resource. Such devices became known as appliances because of the similarity in role or management to a home appliance, which are generally closed and sealed, and are not serviceable by the user or owner. The hardware and software are delivered as an integrated product and may even be pre-configured before delivery to a customer, to provide a turn-key solution for a particular application. Unlike general purpose computers, appliances are generally not designed to allow the customers to change the software and the underlying operating system, or to flexibly reconfigure the hardware.

VHD and its successor VHDX are file formats representing a virtual hard disk drive (HDD). They may contain what is found on a physical HDD, such as disk partitions and a file system, which in turn can contain files and folders. They are typically used as the hard disk of a virtual machine, are built into modern versions of Windows, and are the native file format for Microsoft's hypervisor, Hyper-V.

Hardware-based full disk encryption (FDE) is available from many hard disk drive (HDD/SSD) vendors, including: ClevX, Hitachi, Integral Memory, iStorage Limited, Micron, Seagate Technology, Samsung, Toshiba, Viasat UK, Western Digital. The symmetric encryption key is maintained independently from the computer's CPU, thus allowing the complete data store to be encrypted and removing computer memory as a potential attack vector.

The subject of computer backups is rife with jargon and highly specialized terminology. This page is a glossary of backup terms that aims to clarify the meaning of such jargon and terminology.

<span class="mw-page-title-main">Clonezilla</span> Drive cloning software

Clonezilla is an open-source suite of disk cloning, disk imaging and system deployment utilities. Clonezilla Server Edition uses multicast technologies to deploy a single image file to a group of computers on a local area network. Clonezilla was designed by Steven Shiau and developed by the NCHC Free Software Labs in Taiwan.

Secure USB flash drives protect the data stored on them from access by unauthorized users. USB flash drive products have been on the market since 2000, and their use is increasing exponentially. As both consumers and businesses have increased demand for these drives, manufacturers are producing faster devices with greater data storage capacities.

References

  1. 1 2 3 4 5 Panichprecha, S.; Pongsawatkul, N.; Mitrpant, C.; Ketprom, U.; Kovintavewat, P. (2011). "Multi-threading in disk cloner". The 8th Electrical Engineering/ Electronics, Computer, Telecommunications and Information Technology (ECTI) Association of Thailand - Conference 2011. pp. 512–515. doi:10.1109/ECTICON.2011.5947887. ISBN   978-1-4577-0425-3. S2CID   15754588.
  2. ↑ Turriza, José Luis Lira; Huh, Yaqueline Pech; Lira, Jose Manuel (2018). "Comparative study of restoration tools by cloning using LSP me-thod". Revista Ingeniantes. 5 (1): 1.
  3. ↑ Hayes, Darren R. (2014). A Practical Guide to Computer Forensics Investigations. Pearson Education. pp. 86–87. ISBN   9780132756150.
  4. ↑ Jeanvoine, Emmanuel; Sarzyniec, Luc; Nussbaum, Lucas (2013-02-01). "Kadeploy3: Efficient and Scalable Operating System Provisioning for Clusters". USENIX Association. 38 (1): 38.
  5. 1 2 "Everything You Should Know About Hard Drive Duplicators". MiniTool. 2021-12-28. Retrieved 2023-01-09.
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  7. ↑ Manson, Dan; Carlin, Anna; Ramos, Steve; Gyger, Alain; Kaufman, Matthew; Treichelt, Jeremy (2007). "Is the Open Way a Better Way? Digital Forensics Using Open Source Tools". 2007 40th Annual Hawaii International Conference on System Sciences (HICSS'07). pp. 266b. doi:10.1109/HICSS.2007.301. S2CID   15273267.
  8. 1 2 Meffert, Christopher S.; Baggili, Ibrahim; Breitinger, Frank (2016-08-07). "Deleting collected digital evidence by exploiting a widely adopted hardware write blocker". Digital Investigation. 18: S87–S96. doi: 10.1016/j.diin.2016.04.004 . ISSN   1742-2876.
  9. ↑ Babalola, Olawunmi (2018-03-02). "BEST PRACTICE FOR COMPUTER IMAGING AND MAINTAINING A DATABASE". Student Scholarship – Computer Science.
  10. ↑ "How to Clone Hard Drive on Windows 10 without Reinstalling". www.diskpart.com. Retrieved 2023-01-09.
  11. ↑ "How to Upgrade HDD to SSD without Reinstalling Windows". www.diskpart.com. Retrieved 2023-01-09.
  12. ↑ "Fixed: Cloned Hard Drive or SSD Won't Boot". www.diskpart.com. Retrieved 2023-01-09.
  13. ↑ Yao, J. F. J., & Carlisle, J. (2011). Self-support computer science lab. Journal of Computing Sciences in Colleges, 26(4), 64-70.
  14. 1 2 Grasdal, Martin; Hunter, Laura E.; Cross, Michael; Hunter, Laura; Shinder, Debra Littlejohn; Shinder, Thomas W. (2003-01-01), Grasdal, Martin; Hunter, Laura E.; Cross, Michael; Hunter, Laura (eds.), "Chapter 8 - MCSE 70-293: Planning, Implementing, and Maintaining a High-Availability Strategy", MCSE (Exam 70-293) Study Guide, Rockland: Syngress, pp. 559–638, ISBN   978-1-931836-93-7 , retrieved 2023-01-09
  15. ↑ JasonGerend (7 December 2022). "Volume Shadow Copy Service". learn.microsoft.com. Retrieved 2023-01-09.
  16. ↑ Leschke, T. R. (2010). Shadow volume trash: $ Recycle. Bin forensics for Windows 7 and Windows Vista shadow volumes.
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