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What is RAID 5 and how is it used?

What is RAID 0 and why is it used?


Although the standard is not a Redundant Array of Independent Disks, RAID 0 has a permanent place in the list of popular RAID levels (this is the written form of RAID). This form of linked hard disks does not implement the essential notion of redundant data storage. A single logical drive is generated in a RAID 0 array, which always consists of at least two storage media that are as identical as feasible. Its sole purpose is to maximize read and write accesses. As with other RAID levels, there is no additional data security.

What exactly is RAID 0?


A graphic depicting the RAID 0 working principle.
RAID 0's pros and downsides in a nutshell
What are some common RAID 0 deployment scenarios?
What are some other popular RAID levels?
What exactly is RAID 0?
RAID 0 is a standardized RAID level that outlines the use of two or more hard disks in order to improve performance. On the participating storage media, all data is partitioned uniformly into "stripes" or blocks for this purpose. As a result, the underlying method is also known as "striping." During the write operation, hard disk 1 gets data block "A1," while hard disk 2 stores data block "A2" at the same time. When combined, the two blocks yield data set "A" or a subset of this data set (depending on the size). If the data set is needed later, it can be read in parallel in the same way it was on the hard disks.

Note
In technical circles, the size of the individual blocks is referred as as striping granularity or chunk size. It is usually 64 kilobytes in size (kB).

Striping is used in RAID 0 to increase read and write performance. When a disk fails, however, the data is frequently lost because the remaining disks have merely saved their individual stripes.

Definition


A RAID (Redundant Array of Independent Disks) is a logical drive that is made up of at least two distinct storage media. The relevant hard disk installations, which are defined in RAID levels such as RAID 0, dictate the concrete function. The main points are data security and increased data throughput.

In theory, the number of hard disks that make up a RAID 0 array, i.e. a collection of various hard disks configured according to the RAID 0 standard, is unimportant. Naturally, the more disks there are, the more complicated and time-consuming managing them becomes - the operating software that connects all the disks to make a logical drive becomes more demanding with each additional component.

Four hard disks are presented as an example in the diagram below. The identical data sets "A," "B," and "C" are dispersed evenly so that each storage medium contains a quarter of the respective data strip.


RAID 0's pros and downsides in a nutshell


The ability to parallelize data accesses is a significant advantage of a RAID 0 array over a single hard disk. Not only does the array enhance bandwidth, but it also increases the number of possible input/output operations per second (IOPS). However, because SSD memories lose performance in RAID arrays, this advantage is lost or greatly reduced for subsequent storage generations. As a result, RAID 0 is even more geared toward the use of HDD hard disks than other RAID types.

When compared to a single storage medium, the higher risk of failure is the most significant disadvantage: Because any hard drive in the array can fail due to hardware or software issues, the entire system can fail at the same time. As a result, the following applies: The danger of a total failure rises in lockstep with the number of connected data carriers.

This is made worse by the fact that if a separate backup mechanism is used, such a scenario almost always results in the loss of the majority of the stored data. As previously stated, RAID 0 provides no redundancy when compared to other RAIDs. As a result, after the failure, a reconstruction of bigger data stripes that were shared among all RAID components will be missing the parts of the failed disk. Only smaller files housed on individual RAID 0 memory that are still intact can be recovered.

RAID 0 Advantages RAID 0 Disadvantages


Greater bandwidth than individual drives Single drives have a higher failure rate.
Input and output operations per second are higher than single drives (HDD) Because of the lack of redundancy, much of the data is lost if a drive fails.
Tip
Regular backups are necessary for long-term protection of sensitive and confidential data.

What are some common RAID 0 deployment scenarios?
It's evident from the RAID-0 array's strengths and disadvantages which kind of projects this storage method is best suited for: RAID 0 provides exceptional performance values that clearly outperform solitary HDD performance. Non-critical programs, such as audio or video editing software, that require data to be read and written quickly, benefit greatly from this. In this scenario, a RAID 0 system is clearly a more cost-effective option than an SSD. Due to the absence of redundancy, the approach is not suitable for storing sensitive information such as client data or private files.

Data is stored quickly.


What are some other popular RAID levels?
RAID 0's unique selling point is the lack of a backup mechanism. Other specified RAID levels rely on data loss prevention technologies. Some methods, such as RAID 1 or the RAID 10 combination, rely on data mirroring: Every file is kept on at least two distinct hard drives. In the event of a hardware failure, other types, such as RAID 5 and RAID 6, rely on parity information generated during the write operation to restore data.

Logical data loss on RAID

  • Firmware Update Failed
  • Configuration of the RAID controller deleted
  • Deleting folders and files
  • Deleting share folders
  • RAID formatting
  • RAID accidentally disbanded
  • Loss of array data
  • Loss of the order of the hard disks
  • Encrypted volume damaged
  • Accidental deletion of the array volume
  • Virus attack, Trojan horse

Symptoms of RAID failure

  • Shares not accessible
  • In degraded mode Read only
  • Invalid RAID volume
  • Critical state of the array / composite
  • Network share disappeared
  • RAID offline
  • RAID critical
  • RAID is reported as degraded
  • Storage - compound offline
  • Symptoms of RAID failure
  • volume crashed
  • Volume crashed / lost

Mechanical damage to RAID

  • Bad Blocks or defective sectors
  • Damaged read-write heads
  • Defective RAID controller
  • Defect of the server mainboard (integrated RAID controller)
  • Defective PCB (Printed Circuit Board) Hard disk drive circuit board
  • Data loss caused by fire
  • Data loss caused by water
  • Hard drives Firmware error
  • Falling, crash and impact damage
  • Hard disk damages due to natural disasters
  • Head-Crash with hard disk in RAID
  • HDD failure due to wear and tear
  • HDD failure due to overheating
  • Motor damage to hard disk
  • Surface damage of hard disk in RAID
  • Problems with the servomechanism
  • Rebuild for mechanically damaged hard disks
  • Damaged surface within the service area

Symptoms of RAID failure

  • Device I/O error
  • Plate failed
  • No drive
  • Failed hard disk
  • Shares not accessible
  • In degraded read only mode
  • Invalid RAID volume
  • Critical state of the array / composite
  • LED on RAID hard disk red
  • Multiple hard disk failure
  • Network share disappeared 
  • RAID critical
  • RAID offline
  • RAID server beeps, beeps
  • RAID is reported as degraded
  • Server does not start or boot
  • Storage - compound offline
  • Volume crashed / lost
  • volume crashed
empty