For over thirty years, “RAID” configurations have been widely used throughout the IT-sphere to improve the reliability and performance of storage solutions. This technology’s lifespan demonstrates its usefulness, long before the advent and widespread use of solid-state drives, beginning with hard disk drives.
Because of the dramatic advancements in storage array technology since the introduction of RAID, the way this methodology is used has shifted a great deal.
In a tech industry filled with acronyms and abbreviations and seemingly countless options, what do you need to know about RAID? What does it stand for, and what can it do for you?
What is RAID?
Solid-state drive (SSD) RAID is a particular methodology of storage to protect data. Data protection is achieved by evenly distributing blocks of redundant data across multiple SSDs.
RAID is an acronym for "redundant array of independent disks." While the phrase initially premiered in the 1980s and stood for "redundant array of inexpensive disks" when mechanical hard disk drives were the main form of storage, this acronym now reflects the use of multiple disks across a single array.
The primary purpose of RAID is to increase tolerance of faults and shield organizations from data loss due to a drive failure event. Since its inception so many years ago, many storage systems don't rely on applying RAID protocol throughout the entire drive. Now, redundancy applies to data at a block level, distributed across multiple SSDs.
Essentially, RAID increases the speed to store and access data while limiting data and downtimes.
The Three Major Concepts that Make RAID Storage Tick
How is RAID storage achieved? What makes this storage technique work?
According to HostAdvice, RAID is a kind of technology for “configuring and supporting various combinations of physical hard drives with the aim of improving reliability, performance, and capacity. It consists of multiple physical disks and a controller to configure and manage them.”
Here are three separate techniques that all work to distribute data:
- Mirroring data: Data is written in two separate drives at the same time
- Striping data: Data is split evenly on two or more drives as it is written
- Parity: Raw binary data passes through an operation which calculates a binary result, also known as a parity block, and that result is stored. This aids in redundancy and error correction.
About RAID Levels
RAID-based storage is divided into different levels. Each level refers to a particular technique of distribution, organizing, and managing data across an array in various disks. Every level has its own characteristics, with different levels of fault tolerance, data redundancy, and performance properties. Which level an organization chooses depends on its storage requirements, goals, and costs based on your need for stronger performance and better data protection.
Standard RAID levels are determined by their configurations, which cover a wide range of needs. These levels are RAID 0, 1, 2, 3, 4, 5, and 6. Levels 1, 5, and 6 all offer fault tolerance but level 0 doesn’t. However, level 0 offers the fastest performance. What do you need to know about each level?
- Level 0: A RAID 0 level has the fastest performance, using block-striping techniques for data distribution, and is best for applications that process non-critical data. It requires at least two drives and offers maximum storage space.
- Level 1: RAID 1 mirrors data, and requires two or more drives, provides better data redundancy and data availability for those that need it. It does use parity protocols.
- Level 2: RAID 2 is not widely used but employs bit-level striping with parity. It requires an extra drive to store parity information for error detection and is used to protect against data loss due to corruption.
- Level 3: This level requires three drives, one of which is used to store parity information. It offers the highest level of data transfer rates for large files, but not when there are many requests like a database.
- Level 4: This level is comparable to RAID 3, but data from each drive is accessed independently, one block at a time, which can slow read and write operations. It’s best used for sequential data access and isn’t utilized often.
- Level 5: RAID 5 combines block-level striping with distributed parity for a cost-effective option that balances redundancy, performance, and storage capacity. It requires at least three drives and is not able to survive multiple failures or rebuild data quickly. It’s a solid choice for applications and file servers with limited storage devices.
- Level 6: This level uses block striping and dual-distributed parity for better redundancy and fault tolerance, and can survive two failures simultaneously. It requires at least four drives and is common in serial AT attachment (SATA) environments data archives where long data retention is necessary.
It’s possible to combine and “nest” RAID levels, which typically combines RAID 0 with another level for better performance and redundancy. This gives organizations better performance and higher failure tolerance.
The Perks of Using RAID for Flash Arrays Over RAID-Based Hard Disk Drives
For the most part, RAID-based storage protocol doesn't necessarily mean pooling multiple solid-state drives to improve overall performance. Flash-based SSDs already boasts a better performance rate than hard disk drives (HDDs). Instead, SSD-based RAID is designed to protect data in the event of a drive failure and does so much better than the HDD alternative. Consequently, when an HDD fails, the whole drive is lost —plus the data stored there.
The difference? With an SSD, only part of the drive might fail. This means that there’s less chance of total data loss with an SSD-RAID array.
Even though RAID arrays have been around since the 1980s to improve the performance of HDD storage systems, a single SSD-RAID array can offer better performance over many HDD-RAID arrays, with far better performance to boot.
Rather than think of SSDs as an alternative to RAID, SSDs can be a complement to RAID. This is because an SSD-RAID array is far superior to an HDD-RAID array in performance.
Is a RAID SSD Right for You?
Should you choose an all-flash array that implements a RAID methodology? Some modern servers have fast enough SSD drives that they won’t need the slight performance boost that RAID offers. However, websites and critical online and offline applications should use RAID to prevent data loss, limit or eliminate downtimes, and increase performance at the same time.
- For high-reliability applications
- For applications that require large amounts of storage
- For applications that need high data transfer speeds
- For those that need to add redundancy to assure reliability and availability of a website even during a failure
- For those looking to power their servers and backup systems
- For better data protection and faster data recovery
When it comes to protecting the data in your all-flash array, there are countless configurations available. To receive the maximum results, you can optimize with VIOLIN Systems by increasing your profitability, improving speed, and reducing your IT costs with the VIOLIN QV2020 all-flash storage platform. Being an industry leader in all-flash storage arrays is why managed service providers power their work on our solutions.Thanks to the infrastructure of the QV2020, leveraging RAID architecture, you can eliminate the challenges presented by failures and data loss. Want to learn more about what the QV2020 can do for you? Contact us today!