Disk mirroring is a preservation technique that duplicates data to other hard drives as it is written. For example, when you save a picture to a computer, the data is automatically duplicated to other hard drives connected to it or the network. If one disk gets corrupted, you can still retrieve a file from the mirrored hard drives. This technique ensures you always have a backup of any data written to a disk.

In disk mirroring, hard drives are connected to one another through a disk controller card, an electrical computer component that enables hard drives to communicate with each other. Disk mirroring is also called “Redundant Array of Independent Disks 1 (RAID 1).”

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When shooting conversation and action scenes in movies, directors often use two or more cameras to ensure they are captured well. This strategy lessens the risk of reshooting scenes in case some angles are unclear. Disk mirroring works similarly.

As you create files and make changes to documents, the data is simultaneously reflected in mirrored drives. The image below shows a simple representation of disk mirroring.

Disk Mirroring

What Is the Purpose of Disk Mirroring?

The primary purpose of disk mirroring is to protect a computer owner from data loss stemming from disk failures, data recovery issues, disasters, and other reasons. Therefore, disk mirroring is a form of data backup done in real-time, reducing the need for regular manual creation of data backups.

How Is Disk Mirroring Set Up?

Disk mirroring can be set up using an online connection. Another hard drive in a different location or computer is configured to get updated with data from another disk over the Internet. Most of the time, the second drive is located in an entirely different place to avoid data loss due to fires and other disasters.

Another method to set up disk mirroring is through using RAID, which could be the most popular among institutions.

What Is RAID?

An integral concept in disk mirroring is RAID, which is a way of grouping different disks together. The interconnected disks form a larger hard drive referred to as a “RAID set.” There are different RAID levels or types of RAID sets, and disk mirroring uses RAID 1. Another typical RAID level is RAID, also known as “disk striping.”

How Does RAID 0 Differ from RAID 1?

RAID 0 and RAID 1 are two RAID configurations that serve different purposes and offer distinct advantages and disadvantages. Their primary difference lies in the trade-off between performance and data redundancy.

RAID 0 offers improved performance but no data redundancy. It’s suitable for disk striping where speed is critical, but data backup is handled separately. RAID 1, meanwhile, provides data redundancy and fault tolerance but doesn’t offer the same level of performance improvement as RAID 0. It’s used in disk mirroring where data integrity is a top priority.

Choosing between RAID 0 and RAID 1 or other RAID levels depends on your specific requirements for performance, data protection, and storage capacity. Many organizations use a combination of RAID levels to balance their needs for performance and redundancy.

What Is the Difference between Disk Mirroring and Disk Striping?

While disk mirroring entails simultaneously copying an entire chunk of data to other hard drives, disk striping works differently. In disk striping, data is segmented into multiple blocks, and each component is stored in multiple drives.

As you may imagine, disk mirroring could be slower than disk striping since entire chunks of data are copied in real-time instead of distributing smaller chunks to different disks. However, disk striping may not be as reliable. When one drive crashes or gets corrupted, all of the data could be lost.

Advantages and Disadvantages of Disk Mirroring

Disk mirroring is easy to implement. All you need is a disk controller card to connect multiple hard drives or an Internet connection to link disks in different locations. Moreover, all data remains accessible even when one drive fails. Data can simply be copied from one of the mirrored disks to a replacement drive.

Still, there are downsides to disk mirroring that have to be considered. For one, the data storage capacity is reduced in half since data is being copied completely, making it redundant. For example, saving 5GB of data would take up 10GB of space. That leads to another disadvantage—the cost involved. You would need twice the number of hard drives to store a specific volume of data.

The logic and purpose behind disk mirroring are as simple as it sounds. It simply means having the replica of any data on a different disk so you have a backup in case one hard drive fails. You may even be applying the concept if your phone is set up to automatically sync photos, contacts, and other files to cloud platforms, such as Google Drive and iCloud.

Key Takeaways

  • Disk mirroring is a data protection technique that duplicates data to other hard drives in real-time.
  • It protects data from loss due to data recovery issues, disasters, disk failures, and other reasons.
  • Disk mirroring can be set up through an online connection or via RAID.
  • RAID is a way of grouping different disks together to form a larger hard drive called a “RAID set.”
  • Disk mirroring is similar to backing up data to the cloud, such as Google Drive and iCloud.