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What is a RAID :
RAID (redundant array of independent disks) is a way of storing the same data in different places. How cool is that right !?. Imagine a virtual disk technology that will help you to store data more securely and less vulnerable to any physical damage to your hard disks. RAID combines multiple physical drives into one unit. RAID can create redundancy, improve performance, or do both.
The following are terms that are normally used in connection with RAID:
Striping: data is split between multiple disks.
Mirroring: data is mirrored between multiple disks.
Parity: also referred to as a checksum. Parity is a calculated value used to mathematically rebuild data.
Different RAID levels exist for different application requirements.
How RAID 5 works:
The benefits of RAID 5 primarily come from its combined use of disk striping and parity. Striping is the process of storing consecutive segments of data across different storage devices and allows for better throughput and performance. Disk striping alone does not make an array fault tolerant, however. Disk striping combined with parity provides RAID 5 with redundancy and reliability.
RAID 5 used parity instead of mirroring for data redundancy. When data is written to a RAID 5 drive, the system calculates parity and writes that parity into the drive. While mirroring maintains multiple copies of data in each volume to use in case of failure, RAID 5 can rebuild a failed drive using the parity data, which is not kept on a fixed single drive.
By keeping data on each drive, any two drives can combine to equal the data stored on the third drive, keeping data secure in case of a single drive failure. Drives can be hot-swapped in RAID 5, which means a failed HDD can be removed and replaced without downtime.
RAID 5 layout
At least three drives are required for RAID 5. Depending on where the parity blocks are located and in which order the data blocks are written, there can be four different types of RAID 5. Left and right arrays are determined by how the parity blocks are distributed onto the member disks. Synchronicity and asynchronicity define the order of the data blocks.
RAID 5 is one of the most common RAID configurations and is ideal for application and file servers with a limited number of drives. Considered a good all-around RAID system, RAID 5 combines the better elements of efficiency and performance among the different RAID configurations.
Fast, reliable read speed is a major benefit. This RAID configuration also offers inexpensive data redundancy and fault tolerance. Writes tend to be slower, because of the parity data calculation, but data can be accessed and read even while a failed drive is being rebuilt. When drives fail, the RAID 5 system can read the information contained on the other drives and recreate that data, tolerating a single drive failure.
Longer rebuild times are one of the major drawbacks of RAID 5, and this delay could result in data loss. Because of its complexity, RAID 5 rebuilds can take a day or longer, depending on controller speed and workload. If another disk fails during the rebuild, then data is lost forever.
Additionally, while the backup provided by RAID configurations can contribute to business continuity, they are not equivalent to a disaster recovery setup in which hardware is located in both on-premise and off-premise locations.
Software vs. hardware RAID
RAID can be in the form of hardware or software, depending on where the processing occurs. Software RAID is a form of RAID performed on the internal server. Because it processes on the internal server, software RAID is slower than hardware RAID. However, because hardware RAID requires purchasing additional hardware, software RAID costs less.
How to set up software RAID 5?
A software RAID 5 requires three disks at least; it not only can enhance the efficiency of the disk but also provide the best fault-tolerant. A RAID 5 is a fault-tolerant volume in which the data is striped across an array of three or more disks. Parity (a calculated value that can be used to reconstruct data after a failure) is also striped across the disk array. If a physical disk fails, the portion of the RAID 5 that was on that failed disk can be recreated from the remaining data and the parity.
Open disk management and right-click the unallocated space and choose “New RAID-5 Volume”.
Then click on “Next” in the pop-out “New RAID-5 Volume Wizard”.
Then select the disks you want to use for creating RAID-5 volumes, and click on “Next”. At least 3 disks will be required.
Now, you can assign a drive letter to the RAID 5 volume and format the volume and click on “Next”.
At last, click on “Finish”.
Check the OS version of your server before configuring RAID to know the support scope of the RAID.