Engadget Guide Explains How to Turn Old Hard Drives Into a RAID Array

According to Engadget, cloud storage is everywhere and SSDs have become cheap enough that most new PCs no longer include a spinning drive, despite an ongoing memory crisis. But old hard drives can be combined rather than discarded. RAID stands for Redundant Array of Independent Disks. The idea is to combine multiple disks so they function as a single unit. Instead of storing files on a single drive, RAID distributes them across two or more disks, which results in much faster transfer speeds. The guide says RAID will not match SSD speeds but is much faster than a conventional HDD.

Engadget says a RAID array also provides redundancy for data, because it is less prone to failure. If one drive fails, users can still recover files from another. That is the main reason RAID is still used today, according to the guide, which says the appeal is less about faster speeds and more about convenience and reliability. RAID does not replace a full backup, but it ensures that data will not be lost if one hard drive fails completely.

The guide warns that there are many details to understand before setting up a RAID array. There are four different categories, and each drastically changes the results of combining disks. The best-known are RAID 0, RAID 1, RAID 5 and RAID 10. Understanding each is important so users know what to expect.

RAID 0 combines two or more disks into a single unit without parity, Engadget says. This process, known as striping, speeds up file read and write times. It can be useful for large files such as videos or databases because it combines the total storage space of all drives. The downside is that RAID 0 offers zero data protection. If a drive fails, everything is lost. In short, it is a way to get faster speeds, but not to keep data safe.

RAID 1 writes exactly the same data to every disk in the array, according to the guide. If one disk fails or disconnects, the data remains on the other. That makes it suitable for important projects, though it is not flawless. Users also get faster speeds but sacrifice storage space. RAID 1 uses 50 percent of total capacity to create a mirrored copy. For example, two 1TB drives can store only up to 1TB of files instead of 2TB.

RAID 5 and RAID 10 are more complicated, Engadget says. With RAID 5, data is divided into blocks and written across multiple drives. It requires at least three drives, and if one fails, data is not lost. The system uses the remaining drives and algorithms to automatically reconstruct the missing data. RAID 10 works like a combination of RAID 0 and RAID 1. Multiple drives are grouped into pairs, and each pair has a copy of its data. If a single drive fails, there is no problem, but if a mirrored pair fails, data could be lost.

There are different ways to set up a RAID array, depending on the operating system and hardware. A user can connect two or more disks to a computer and create a RAID array using software. This is usually the easiest way, but performance will not be optimal. Apple's Disk Utility in macOS lets users set up RAID 0 and 1 arrays, similar to Disk Management in Windows. Paid software such as StableBit DrivePool and SnapRAID offers additional features.

For users who want to take RAID seriously, Engadget recommends hardware-based methods. These use dedicated controllers that better protect drives against failures and deliver better performance, but they are more complicated to set up. Users may have to buy a RAID controller to install on the motherboard. Those who do not want that trouble, or who have a mini PC, might choose a RAID enclosure. These usually come with a RAID chip built in, so drives only need to be plugged in. The guide advises checking maximum capacities and speeds before buying, because high speeds are not guaranteed.