Hard drive crashes remain a leading cause of data loss, and while solid-state drives (SSDs) offer better performance and (arguably) better reliability, they’re still a single point of failure.
If an HDD or SSD fails, you lose data — unless you have a backup. But what about RAID arrays?
RAID stands for Redundant Array of Inexpensive Disks (or Redundant Array of Independent Disks). Many RAID configurations offer high levels of redundancy, which means that a single hard drive failure will not lead to data loss. In fact, depending on the implementation, multiple simultaneous hard drive failures may not cause data loss.
On paper, this makes RAID a great option for consumer data storage. However, before purchasing a RAID, make sure you understand what you’re getting into. Here’s what home computer users should know.
Owning a RAID doesn’t mean that you’re “backing up” your data.
Before you shell out money for a RAID, it’s important to understand the difference between backup and redundancy.
- Data backup is the process of making copies of your data. A good backup strategy protects against data loss.
- Redundancy ensures the continuity of a system. It removes a single point of failure, which enables your system to keep running if a piece of hardware (namely, your hard drive) fails.
If your data only exists on a RAID array, it’s not backed up. While a media failure poses less of a threat to your data, it’s still a threat — you still need backup.
We strongly recommend keeping at least three copies of all important files including one off-site copy, which provides protection against fires, floods, and other natural disasters. Proper backup is important, regardless of the device you’re using for primary storage.
So, is redundancy important for your home computer? That depends on the application and the RAID level.
Related: The Dangers of DIY RAID Data Recovery Efforts After ‘Offline’ Failure
Common RAID Levels and Their Applications
Many types of RAID exist, and some aren’t truly redundant. Most home RAIDs use one of the following technologies:
- RAID 0 stripes data across all of the drives in the array. As a simple example, a file consisting of two bits of data might be equally spread across a two-drive RAID 0 (each drive receives one bit). RAID 0 does not offer redundancy, so it’s not a true RAID, but it offers faster performance than a single hard drive.
- RAID 1 mirrors data across the drives in the array. In a two-drive RAID 1, each hard drive has identical data. If one hard drive fails, the data is still accessible. However, RAID 1 doesn’t offer faster performance than an individual hard drive, and it doesn’t use data efficiently.
- RAID 5 uses block-level striping with a distributed parity. The parity provides redundancy while using data more efficiently than a RAID 1. With a three-drive RAID 5, data is distributed evenly across each of the three drives, but the parity ensures that if one drive fails, there is no data loss.
RAID 5 is faster than RAID 0 or RAID 1, but to write data, you’ll need either a hardware controller card or RAID software.
Hardware controllers are generally a better option — they write data efficiently, independently from the computer’s operating system. Of course, there’s a downside, which we’ll discuss in the next section.
Related: RAID Storage Systems -SSD vs. HDD Comparison
A hardware RAID creates a (new) single point of failure.
One of the primary advantages of a RAID (with the exception of RAID 0) is that it prevents a single hard drive failure from causing data loss. However, hardware RAIDs rely on a controller card to manage read/write processes.
If the controller card fails mid-operation, data loss can occur. In our experience, inexpensive RAID controllers are more likely to cause issues like corruption — so if you’re committed to RAID, research controller cards carefully before making your purchase.
Related: Software RAID vs. Hardware RAID: Advantages and Drawbacks
RAIDs offer better performance than individual hard drives, but they’re more expensive.
Most RAID levels can complete read/write operations much faster than an individual hard drive. But if you don’t need the extra performance — or redundancy — you should focus on building a strong backup strategy before considering RAID.
With that said, RAID is appropriate for home computer users in certain situations:
- If you’re running a server, RAID can help you prevent downtime.
- If you’re backing up large amounts of data regularly, redundancy can spread the work across a number of hard drives. That may reduce your storage media expenses over time (and you won’t have to stop everything to replace a failed hard drive).
- The performance advantages of striped RAID arrays are considerable. If a single SSD isn’t fast enough for your application, RAID makes sense.
If you decide to purchase a RAID, read the documentation. Make sure you understand how to restore the data after a hard drive failure — and if data only exists on the RAID, consult with a professional data recovery provider before attempting to rebuild the array. A failed rebuild can cause permanent data loss, so treat RAID failures as serious events.
Related: How We Recovered All Data From an Incorrectly Rebuilt RAID Array
Trust the leader in RAID data recovery.
Datarecovery.com is the world’s leading provider of RAID data recovery services. With risk-free evaluations and our no data, no charge guarantee, we provide peace of mind during data disasters — and fast access to mission-critical files.
To learn more about our services, call us at 1-800-237-4200 or submit a case online.
