What are the Several Popular RAID Systems/Levels?

Summary – This blog highlights RAID and its different popular levels that help increase data availability by use of multiple hard disks, which further improves performance. It also suggests a third-party RAID Recovery solution in case they become corrupt or damaged.

If you are looking forward to purchasing a RAID server for your own business, or for anybody else’s business, or for the firm you are working with, you may want to know about the several popular RAID systems so as to select the best one. The reason being, there are several, which may leave you confused. To set you at ease, let’s look at RAID and its various levels that have gained popularity, and also touch upon RAID corruption and RAID data recovery.  There are a brief of advantages and disadvantages of popular raid systems.

What is RAID?

Redundant Array of Independent Disks or RAID as is popularly called is a data storage virtualization technology wherein multiple physical hard disks are arrayed in one logical case for drive redundancy. This increases reliability, availability, storage capacity, and hence, the overall performance. The performance is improved in such a way that if one disk fails, the redundant ones make up for the failed disk by making the data available.

Here, data is distributed in several ways across the disks and are referred to as RAID levels such as RAID 0, RAID 1, RAID 2, RAID 5, RAID 10, etc. depending on the redundancy level and performance required. Each of these RAID levels provides a different balance among the key RAID goals that are availability, reliability, data storage capacity, and in turn, performance. RAID levels other than RAID 0 provide protection from unrecoverable sector read errors and from failures of entire physical drives.

Advantages and disadvantages of popular raid systems

The Different Popular RAID Levels

The different popular RAID levels are defined and described in the sections below:

RAID 0 – Using striping technology without the use of mirroring or parity the data in RAID 0 system is split almost equally into blocks that get written across all the disks in the array. Here, the storage capacity is the sum of the capacities of all the disks in the array same as with a spanned volume. By using at least 2 disks simultaneously, it offers superior input-output performance. This performance can be enhanced further by using multiple controllers; ideally, it is one controller per disk. However, there is no added redundancy or fault tolerance for handling disk failures, same as with a spanned volume. Thus, failure of one disk causes complete data loss and considerably reduces the possibility of Raid data recovery in comparison to a broken spanned volume. This RAID level is ideal for non-critical storage of data that have to be read or written at high speed such as on a video editing station or image retouching.

Advantages

  • Good performance in both read and write operations
  • Complete storage capacity is utilised. Here, overhead is not because of parity controls
  • Easy-to-implement technology

Disadvantages

  • It is not fault-tolerant

RAID 1 – Using mirroring technology with no parity, striping, or spanning of disk space across multiple disks RAID 1 consists of an exact copy or mirror of data on two or more disks belonging to the array. This means that data is stored two times by writing it to both the data disk and the mirror disk. This array is useful when read performance is important as compared to write-performance or the resulting data storage capacity. Moreover, it will continue to operate as long as one disk is in an operational state. Here, if a drive fails, either the controller uses the data or the mirror disk for Raid data recovery and continues operation. This RAID level is ideal for critical data storage. For instance, data from accounting systems. It is also suitable for small servers (Raid Data Recovery) in which only two drives are used.

Advantages

  • Uses simple and easy-to-understand technology
  • Offers excellent read and write speed which is comparable to a single drive
  • In the case of a drive failure, data can be copied to the replacement drive thus avoiding data rebuild.

Disadvantages

  • Usable data storage capacity is only half of the total drive capacity because all data is written twice
  • Does not allow the swapping of the failed drive when it is hot. This means that the failed drive can be replaced only after powering down the computer to which it is connected. So, for a server that is used by many simultaneously, this is not possible at all times.

RAID 5: Consisting of block-level striping with distributed parity among drives, RAID 5 is the most common and secure level. Requiring a minimum of 3 drives, it can work with up to a maximum of 16 drives. Here, data blocks are striped across the disks, and on one disk a parity checksum of all the block data is written. The parity data is not written on a fixed drive but is spread across all the drives. With the use of this data, the computer can recalculate the data of one of the other blocks, should those data be no longer available. That means this type of array can withstand the failure of a drive without losing data. Although it can be achieved in the software, it is recommended to use a hardware controller. Moreover, the extra cache memory is use on these controllers to improve the write performance. Combining efficient storage with excellent security and decent performance, it is ideal for file and application servers having limited drives.

Advantages

  • Read data transactions are fast as compared to write data transactions that are somewhat slow due to the calculation of parity.
  • Data remains accessible even after the drive failure and during replacement of the failed hard drive because the storage controller rebuilds the data on the new drive.

Disadvantages

  • Failed drives have adverse effects on throughput
  • It has a complex technology
  • If one of the drives of large size in the array fails, replacing and restoring the data (or the rebuild time) may take one or more day, depending on the array load and speed of the controller. If another disk gets damaged or corrupt, your data gets lost forever.

Conclusion

All RAID servers including RAID 0, RAID 1, and RAID 5 are known for increasing data availability and reliability by the data redundancy technology. Still, they do fail to make data unavailable for use. In such situations, RAID data recovery becomes a must. In case there is a RAID 0 failure RAID 0 recovery gets essential. In the same way, RAID 1 recovery, and RAID 5 recovery gets essential for corruption or failure in RAID 1 and RAID 5 levels respectively. In such situations, you can go for RAID data recovery services by Stellar Data Recovery as it is the best bet having knowledgeable and experienced technicians for recovering data from failed RAID servers. With the kind of expertise they have, they can do RAID data recovery even in cases of severe corruption.

5 thoughts on “What are the Several Popular RAID Systems/Levels?

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