Introduction
RAID stands for Redundant Array of Independent Disks or Redundant Array of Inexpensive Disks. In computer storage, a basic set of RAID configurations results in the formation of standard RAID levels. These configurations employ various techniques like striping mirroring to create convenient and reliable data stores from various multiple general-purpose computer hard disk drives.
The most common types of RAID levels include RAID (stripping), RAID 1 (mirroring), RAID 5 (parity) and RAID 6 (dual parity). RAID levels can also be combined with one another. Although RAID levels provide good protection against and recovery from hardware defects or hard errors, they are incapable of providing any protection against data loss due to unavoidable catastrophic circumstances like fire, water, or soft errors like user error or malware infection. RAID is only a building block of a larger data loss prevention and recovery scheme.
RAID 1 vs RAID 5
RAID 1
The RAID 1 setup consists of an exact copy (or mirror) of a set of data on two or more hard disks, that is, a classic RAID 1 consists of a mirrored pair containing two disks. This configuration is useful when reading performance or reliability is more important than the resulting data storage capacity. The array continues to operate as long as at least one member drive is operational.
RAID 5
The RAID 5 setup consists of block-level striping with distributed parity. Here, the parity information is distributed among the drives. It requires all drives but one to be present to operate. On failure of a single drive, subsequent reads can be calculated from a distributed parity so that no data is lost. This setup requires at least three disks.
Difference Between RAID 1 and RAID 5 In Tabular Form
| Topic Of Comparison | RAID 1 | RAID 5 |
| Meaning | RAID 1 stands for REDUNDANT ARRAY OF INDEPENDENT DISK LEVEL 1. | RAID 5 stands for REDUNDANT ARRAY OF INDEPENDENT DISK LEVEL 5. |
| Splitting of data | The data is not split among the disks in RAID 1. | The data is equally divided among all the disks involved in RAID 5. |
| Write speed | The write speed of RAID 1 is slower compared to RAID 5. | The write speed of RAID 5 is better than RAID 1. |
| Minimum number of hard disks required | The minimum number of hard disks required in the setup of RAID 1 is 2. | The minimum number of hard disks required in the setup of RAID 5 is 3. |
| Mirroring and redundancy | RAID 1 supports the technique of mirroring and redundancy. | RAID 5 does not support the technique of mirroring and redundancy. |
| Data accessing rate | Data accessing rate in RAID 1 is low. | Data accessing rate in RAID 5 is high. |
| Requirement of memory space | A large amount of space is required in RAID 1 for mirror spacing. | In RAID 5, a large amount of space is not required. |
| Accessing data at the time of data recovery | In RAID 1, one cannot access the data at the time of data recovery. | In RAID 5, one can access the data while recovering the data from failure. |
| Security of data | The security of data is low in RAID 1. | RAID 5 is best suited for medium-level of applications. |
| Suitability for level of applications | RAID 5 is best suited for medium-level applications. | RAID 1 is best suited for the high-end level of applications. |
| Cost | The cost of RAID 1 is high. | The cost of RAID 5 is low. |
| Common implementations | Operating systems (OS), database operations. | Information warehousing. |
What is RAID 1?
RAID 1 stands for Redundant Array of Independent Disks Level 1. It is a popular disk or solid-state drive (SSD) subsystem that increases safety by writing the same data on two drives. Also known as “mirroring”, RAID 1 does not increase performance. Instead, when one of the two drives fails, the second drive is used, and the failed drives are manually replaced. After the replacement of the defective disk, the RAID controller duplicates the contents of the working drive onto the new one. The more number of drives in a RAID 1 array, the lower the probability of failure. RAID 1 aims to improve the devices’ reliability, capability, and performance and help to avoid various faults and errors. The mirroring technique improves the efficiency of securing data and increases the speed of reading, writing, and access. RAID 1 improves the efficiency and performance of the devices and also lowers the risks of data loss.
Functions Of RAID 1
RAID 1 has three main functions to help the users implement the type in their homes and workplaces.
- Mirror or copy the data easily.
- Store the critical and sensitive data.
- Access mission–critical data where redundancy is a must.
Highlights Of RAID 1
The advantages of RAID 1 are listed below:
- Enables people to easily use it.
- Offers good read and write speed.
- Provides good data access speed.
- Ensures data storage efficiency and data security.
Drawbacks Of RAID 1
The drawbacks of RAID 1 are listed below:
- The cost will be higher since it needs twice as many drivers.
- The storage capacity is reduced to half the total of the drive’s capacity.
- All the required devices are required to be powered off while replacing the defective drive.
What is RAID 5?
RAID 5 stands for Redundant Array of Independent Disks Level 5. This RAID type consists of at least three disks for correct work, and a maximum of 16 drives can be added for the sake of efficient performance. Here, the data blocks are striped across the drives, and the parity checksum of all the block data is written on one of the drives. The parity data is not only written in one fixed drive but is spread across all drives. Using this parity data, the computer can recalculate the data of one of the other blocks should those data no longer be available. Therefore, a RAID 5 array can withstand a single drive failure without losing data or access to data.
Highlights Of RAID 5
The advantages of RAID 5 are listed below:
- It provides faster read operation speed.
- It offers a higher level of data redundancy.
- It makes the disk space utilization more efficient.
- It allows multiple users to access it simultaneously.
Drawbacks Of RAID 5
The drawbacks of RAID 5 are listed below:
- At least three drives are required for the implementation.
- The write operation speed is slower.
- The recovery operation speed is slower.
Main Differences Between RAID 1 and RAID 5 in Points
- RAID 1 provides fault tolerance by using the “mirroring” technique whereas RAID 5 offers fault tolerance by implementing the concept of parity and checksum, where the data is striped and stored uniformly across all the drives.
- RAID 1 provides less read operation as compared to RAID 5.
- RAID 1 does not offer a higher level of redundancy as compared to RAID 5.
- RAID 1 provides a better write operation speed as compared to RAID 5
- RAID 1 lacks the feature of rebuilding data when one of the drives fails without powering off the computer, unlike RAID 5.
- RAID 1 does not allow multiple users to access the data simultaneously, unlike RAID 5.
- The recovery speed of RAID 1 is faster compared to RAID 5.
- At least two disks are required for the setup of RAID 1, whereas RAID 5 requires at least three disks.
Conclusion
We can conclude by saying that RAID 1 will be a better option if one wants to use it in a simple implementation, whereas RAID 5 will be more suitable for a complicated system since the underlying technology in each implementation may differ.
References
- RAID – Wikipedia
- Standard RAID levels – Wikipedia
- Common RAID Disk Data Format – Storage Networking Industry Association
