To provide redundancy to data and enhancement.
A RAID card is a device that manages a personal computer's disks and Solid-State Drives (SSDs) to make sure they can work in tandem and provide redundancy or performance.
It could comprise either hardware (a RAID card) or software.
What are RAID Controller Cards?
The RAID controller can be described as a device or chip placed within the OS and storage drives, which are typically the hard drives.
RAID can provide data redundancy or increase the performance of Hard Disk drives. Most RAID levels provide both. RAID provides redundancy for SSDs. However, it doesn't enhance SSD performance.
RAID designed explicitly for SSDs can offer redundancy as well as improve performance.
RAID controller cards operate by dividing drives into distinct groups, with particular redundancy and data protection features.
The front-end interface interfaces with the server, typically through an adapter that is host-based (HBA). The backend connects to and manages the storage media, usually ATA, SCSI, SATA, SAS, or Fibre Channel.
RAID Controller Cards Classifications
RAID controllers are classified based on different characteristics like drives like SATA or SAS and the ports it supports, the number of drives it can support, the specific RAID levels, the interface architecture, and the amount of memory in the native cache.
For instance, this means that a controller explicitly made for a SATA environment won't be compatible with the SAS array.
This also implies a RAID 1 controller cannot be transformed into a RAID 10.
RAID controllers do not function as storage controllers. Storage controllers provide active disks to the OS, and the controller functions in the capacity of a RAM storage cache and functions as a RAID controller.
The RAID controller's setup determines the size and type of RAID disks.
Classifications of Raid Controller Cards
Server-Based RAID
Hybrid Hardware/Software RAID
Server-Based RAID
Software RAID offers RAID services to the host. It is available in two varieties of software-defined hosts hosted within the OS and a hybrid architecture that incorporates a hardware component that relieves the CPU.
The host-based program handles RAID calculations and connects to storage drives via the HBA and a native interface for I/O. It is activated at the time the OS starts the driver for RAID.
Hybrid Hardware/Software RAID
Hybrid software/hardware RAID uses a hardware component to provide RAID BIOS functions directly from your MotherBoard or the HBA.
Hybrid technology is an additional layer and is more expensive than when compared to software-only. However, it safeguards RAID systems from boot errors.
RAID system from boot-up errors in the event of an issue with your operating system.
What are the Different RAID Levels?
RAID controller cards are specialized in their RAID levels. The most commonly used levels are RAID 0 1, 5, 6, and 10. For more detailed information, go to RAID Levels.
Raid 0: Striping
RAID zero is the only RAID level that doesn't offer redundancy but instead improves the performance of hard disks.
RAID 1 divides files, stretches the data over two or more disks, and treats the striped discs as single partitions.
Because it treats multiple disks as one partition, the file is not readable even if one drive fails.
RAID 1: Mirroring
RAID 1 works on two or more desks to provide the ability to redundancy data as well as failover. It writes and reads identical information to every disk.
If a mirrored disk fails, it will store the data entirely on the working disk.
If the failed desk is replaced or repaired, the RAID will mirror the data to the new drive. RAID 1 also increases read performance. The use case is data redundancy and speedier reads at a lower cost.
Raid 5/6: Stripping using Parity/Double Parity
RAID 5/6 is a combination of RAID 0 and redundant features of RAID 1 but requires around one-third of capacity.
"Parity" refers to raw binary data. RAID 5 splits data over two disks and calculates the block-level value to create a parity block. RAID 5 has dedicated parity blocks in a striped HDD.
If a drive fails, RAID 5 uses its particular parity block to reconstruct data for the other nodes. RAID 6 operates like RAID 5; however, it requires at least four disks within an array.
This means that it can keep an additional parity block in each HDD. This creates a highly scalable configuration in which two disks could fail before the array becomes unusable.
RAID 10: Striping and Mirroring
RAID 10 is among the highest-priced of RAID levels. In a four-drive array, the system strips data to two disks. It will stripe at least four disks to improve performance and also has mirrors to provide redundancy.
The other two disks mirror the stripes, each of which holds about half the information. The use case is high-performance and high-security environments like transactional databases with high-speed processing, storing sensitive information.
RAID 10 is by far the highest-priced RAID level available for HDDs; however, it offers superior reading and writing speed and solid data redundancy.
Advantages of RAID Controller Cards
RAID is an essential data protection driver and driver to HDD and SSD and an efficient driver that works with HDD. The top benefits are:
More reliability
Except RAID 0, RAID ensures that a single node that crashes won't bring the array and the array with it.
Applications continue to run on other nodes while the failed node is fixed or replaced, ensuring data consistency and preventing data loss.
Data Redundancy
Mirroring and striping using parity spread data across several nodes, ensuring no loss of data should a device fail.
A higher HDD performance
Most RAID levels increase throughput because they allow applications to write and read information from many drives simultaneously.
It is not an automatic increase as more RAID levels, mainly RAID 10, will eat up the system's resources, making them unsuitable for low and mid-performance arrays.
The arrays that benefit the most are those with RAID for performance enhancement and RAID 5/6 for increased performance and redundancy.
In a high-performance array RAID, 10 increases performance and ensures high availability and redundancy.
Advantages of RAID Controllers
The hardware-based controller architecture of RAID is more costly than software-based RAID. It also improves system performance and isn't prone to boot failures.
Cache Memory
Controller-based RAID typically provides extra Dick cache memory that helps speed up RAID operation.
Processing Dedicated
Controller-based systems can handle RAID configuration independently of the OS. In addition, since RAID controllers do not require the power of a disk processor speed and capacity, they stand over software-only RAID systems.
The Absence of Boot Errors
Because RAID controller cards that are software-only reside within the OS, it is susceptible to boot errors which could cause damage to the entire array. The boot errors won't impact RAID controllers.
