Disk Imaging vs Disk Cloning: Key Differences

In today's technology landscape, disk imaging and disk cloning still play significant roles in IT workflows. But it's crucial to understand the benefits and limitations of each technology before deciding which one to use and how it aligns with your organization's IT infrastructure. While many IT professionals have relied on both techniques for years, some companies are now exclusively adopting disk imaging. 

Defining Disk Imaging and Disk Cloning

Disk imaging and disk cloning are often mistakenly used interchangeably because they achieve the same outcome—creating an exact copy of a drive. This copy includes all data, files, software, the master boot record, allocation table, and other components necessary for booting and running an operating system. However, there are fundamental differences between the two methods.

Disk Imaging: Larger Files, (Sometimes) Slower Restores 

TechTarget defines disk imaging as “software…used to make an image of a completely configured system. Because of its large size, a disk image file is compressed and stored on a secondary storage device or in cloud storage. Hard drive disk images can be saved as a virtual hard disk.” 

Disk imaging involves creating a byte-by-byte archive of a hard drive, resulting in a compressed file format (typically saved as an ISO file). These compressed image files are often stored on external drives or in the cloud due to their substantial size. However, they offer the advantage of granular data restoration.

There are two types of disk image files: full and differential. Full images encompass the entirety of the source drive, while differential images capture only the changes made since the creation of the last full image. As a result, differential images do not contain all the necessary data for drive restoration; a full disk image is required. 

Restoring and accessing data from disk images involves using imaging software to install and open them on a new or existing drive, which can be a time-consuming process. Additionally, disk images can consume significant backup storage space. 

Arcserve ShadowProtect saves your backups as images but eliminates the time it takes to restore data using patented VirtualBoot technology to instantly boot a backup image into a virtual machine. And ShadowProtect lets you run automated, easy-to-use tests on your backup images, so you’ll be sure your backups will work when a disaster strikes.

Disk images differ from snapshots in that a differential image stores the changes made to a file system since the last full image. In contrast, a snapshot reflects the contents of a persistent disk at a specific point in time. Arcserve Unified Data Protection (UDP) software offers hardware snapshot support for fast backups and recovery. 

Disk Cloning: Uncompressed Replication 

TechTarget defines disk cloning as “the act of copying the contents of a computer's hard drive. The contents are typically saved as a disk image file and transferred to a storage medium, such as another computer's hard drive.”

Disk cloning entails creating an exact, uncompressed replica of an entire drive or specific partitions. Since disk clones are uncompressed, they can be immediately replicated to a target backup drive or the cloud, resulting in an up-to-date, identical copy of the data. The critical advantage of cloning over disk imaging is speed. In the event of a hard drive failure, the cloned drive can be quickly replaced, minimizing downtime.

Disk Imaging vs. Disk Cloning: Pros and Cons 

Both disk imaging and disk cloning offer advantages and disadvantages. Cloning excels in some rapid recovery scenarios, while imaging gives you greater backup flexibility. But taking incremental backup snapshots stands out because it lets you store multiple images without using a lot of storage space. Snapshots can be invaluable when recovering from ransomware attacks or other data disasters, where reverting to an earlier disk image is your best chance of recovery.

Bit cloning limits you to a single copy per drive. Although you can overwrite one clone with another, each clone version requires its own drive. Meanwhile, imaging gives you the convenience of remote storage, employing compression to minimize storage demands and letting you store images in a way that best suits your infrastructure.

Find Out Which Is Best for You

By talking to an Arcserve technology partner, you’ll have access to the expertise you need to decide the best data resilience solutions for your organization, including assessing disk imaging vs. disk cloning and where snapshots fit into the picture. 

Find an Arcserve technology partner here.