What Are Standard RAID Configurations
By Tobias Geisler Mesevage
Over 20 years ago, three computer scientists at the University of California, Berkeley, argued that the inexpensive disk drives readily available for the growing personal computer market would out-perform any mainframe disk drive when it came to redundancy and reliability of data storage.
They coined the term “Redundant Arrays of Inexpensive Disks” (RAID) – that term was later changed to Redundant Array of Independent Disks, but the idea remained the same.
RAID distributes data across different disk drives, preventing data loss by increasing performance and reliability of data storage.
While RAID doesn’t supersede the need for backup storage plans, it does offer a safeguard against hardware failure.
In this article, we break down the basics of RAID, why you should use RAID, and the advantages and disadvantages of each RAID level.
What Is RAID?
“Redundant Array of Independent Disks” (RAID) is a data storage virtualization technology that uses multiple physical disk drives to create data redundancy and improved performance.
RAID-enabled systems use two or more hard disks to provide fault tolerance, which ensures your data will be protected in the event of a hardware failure. Establishing fault tolerance can reduce the impact of a disaster, which typically means a loss of productivity, revenue, reputation, and data.
RAID should be considered another powerful tool in your business’ disaster recovery plan. The goal of a good disaster recovery plan is to determine how your organization can access and recover mission-critical data after a disaster.
There are two common practices for protecting data:
- Data Backup: Protect against catastrophic system failure, viruses, and corrupt files
- RAID: Protect against total drive failure
Both are critical to ensuring your data is protected, but RAID is just one building block of a disaster recovery plan.
Choosing The Right RAID Level
How you configure your system’s fault tolerance depends on the RAID level you’ve chosen.
In choosing a RAID level, you should consider:
How the data is distributed across the drives is referred to as RAID levels. Each level represents a different configuration that balances between reliability, availability, performance, and capacity.
There are three basic RAID elements:
- Striping (RAID 0): Provides optimal data reading and writing speed but does not provide fault tolerance. It’s easiest to implement with no overhead cost. It’s most commonly used for non-critical data storage.
- Mirroring (RAID 1): Provides fault tolerance by replicating one disk drive to another. It also reduces storage capacity since the other half is used to duplicate the data
- Parity (RAID 5 & 6): Provides fault tolerance and speed by using a combination of parity and block-level striping. The read speed is quite fast, while the write speed is slow due to parity calculations. When a failed drive is replaced, the lost data is rebuilt on the remaining drives.
Choosing the right RAID level also depends on whether you have hardware or software RAID, which determines how the data is written to disk:
- Hardware RAID: is directly managed by a dedicated hardware controller to which the disks are connected and the RAID processes are managed by an on-board processor. Hardware RAIDS also protect against unexpected power loss with a BBU (Battery Backup Unit).
- Software-based RAID: is usually a part of the operating system and is both the easiest and most cost-effective implementation of a RAID system.
For most businesses, lost data means lost business. Preparing for the event of a network failure, due to natural disasters or a virus, is critical to preventing lost productivity, revenue, and reputation. While RAID is a great way to optimize server performance and quickly recover from hardware failure, it’s only one step of a successful disaster recovery plan.