In this article, I’ll explain “What is Raid or Disk Stripping” in Linux. As we all know data storage is very important for every business organization. Because Data is the important information of any organization. So it is very important to keep the security of data. So if a disk failure occurs then original data destroys. So it becomes very difficult to regain exact data from the failed disk. So to provide certainty on data losses, we copy data on multiple disks and combines them in a virtual volume which we call RAID. RAID stands for Redundant Array of Independent Disk. It’s a virtual disk used to combines the multiple storage devices in the logical volume. It is used to improve redundancy and performance. Raid is the virtual volume which is the combination of multiple physical devices. The virtual volumes are used in different places and in different situations. So the use of virtual volume depends upon the nature of work.
What is Raid? Some organisation uses it for fault tolerance, some uses for improving the redundancy of data and while other uses it for both fault tolerance and redundancy of data. For this, Raid has different Levels as its usage accordance given below.
Most Common Levels of Raid :
Most common raid levels are Raid0, Raid1, Raid5, Raid6, and Raid01. Raid0 is popular for data stripping and providing a good performance of read-write data. While Raid1 is known as Data mirroring storage devices.Because it keeps a copy of same to other drives. Other Raid levels have also some interesting features let’s learn about them.
Features of Raid –
i. RAID 0
Raid 0 uses two or more disks and is often called striping (or stripe set, or striped volume). Data is divided in chunks, those chunks are evenly spread across every disk in the array. The main advantage of raid 0 is that you can create larger drives. raid 0 is the only raid without redundancy.
- It splits data into 2 parts.
- Requires at least 2 physical disks.
- Improve the redundancy of data in the storage device.
- Provide less data reliability.
- Doesn’t provide fault tolerance.
ii. RAID 1
raid 1 uses exactly two disks and is often called mirroring (or mirror set, or mirrored volume). All data written to the array is written on each disk. The main advantage of raid 1 is redundancy. The main disadvantage is that you lose at least half of your available disk space (in other words, you at least double the cost).
- It also requires at least two disks.
- Doesn’t split data, It copies data in other disks.
- Provide reliability over data loss because it makes a copy of data on other disks.
- Provide safety against fault-tolerance.
- Improve performance by providing faster speed of reading and write datagrams.
iii. RAID 2,3 And 4
Raid 2 uses bit-level striping, raid 3-byte level, and raid 4 is the same as raid 5, but with a dedicated parity disk. This is actually slower than raid 5 because every writer would have to write parity to this one (bottleneck) disk. It is unlikely that you will ever see these raid levels in production.
iii. RAID 5
RAID 5 uses three or more disks, each divided into chunks. Every time chunks are written to the array, one of the disks will receive a parity chunk. Unlike raid 4, the parity chunk will alternate between all disks. The main advantage of this is that raid 5 will allow for full data recovery in case of one hard disk failure.
- It is the secured level of Raid among all the levels. Because it has features of RAID 0 & Raid 1.
- Raid 5 requires at least 3 disks and a maximum of 16 disks.
- Neither split data and nor copy data but it store partly data overall disk.
- Provide reliability over data loss because it stores partly data. So if a disk failure occurs then other disks can provide the same data.
- Also, Provide safety against fault-tolerance.
- As data is stored partly so it provides faster performance of data read and write.
iv. RAID 6
RAID 6 is very similar to raid 5 but uses two parity chunks. Raid 6 protects against two hard disk failures.
- It requires at least 4 disks.
- Out of 4 data disk, only 2 disk’s storage capacity is available while the other 2 used for the data mirror.
- So in case if any 1 or 2 disk fails other 2 disks provide data certainty.
- Transfer of data is also faster as like Raid5.
- Also, provide data safety against fault tolerance.
v. RAID 01(0+1)
- It is the combination of Raid 0 and Raid 1.
- Requires at least 4 disks.
- First raid 0 is created and then raid 1 is created over Raid 0.
Also, Read ;
- User management in Linux.
- Compression and Combination of Files or Folders.
- Install Yum Server with ISO File.
This post is all about RAID and its levels. In the next article, we will learn how can we use or create different levels of Raid. I’ll update the next article very soon. So stay connected with me.
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