Answer: The Full Form of RAID is Redundant Array of Inexpensive/Independent Disks.
RAID is a technique of data virtualization that uses multiple hard disks or solid-state drives to provide for data redundancy and performance improvement. Redundancy provides threat resilience to the data in case of unforeseen events, thus proving advantageous over the conventional storage technique of having a “single large expensive disk” (SLED). So instead of having all the data on one SLED, RAID instead makes use of multiple small-sized disks allowing faster I/O operations and providing robustness to the whole system. In case one of the disks in the system crashes the others remain safe and the whole system doesn’t collapse.
History
RAID was first discussed by David Patterson, Randy Katz, and Garth A. Gibson in their technical report, “A Case for Redundant Arrays of Inexpensive Disks (RAID)” in the year 1988. The report discussed and established how RAI could be more resilient and reliable than a single disk.
Characteristics
- Data Redundancy: Data is stored in multiple disks and copies of same data are kept in different locations(disks) for disaster management.
- Use of multiple disks: Instead of using a single large disk, RAID stores data in many small less expensive disks.
- Use of multiple storage techniques:Different RAID levels use different storage techniques like-: striping, mirroring and parity to provide multiple features to the users.
- Multiple Systems:There are 6 different RAID levels and each provides some unique features and compromises on some. It is up to the user and his requirements as to what can be use in their system.
Advantages
- Data access speed: Data access speed in RAID systems is undeniably better that SLED systems. RAID 0, RAID 4 and RAID 5 are specially designed for fast and cheap data access.
- Redundant data: Data redundancy provided by RAID systems provides for a reliable storage system. RAID 1 uses data mirroring to keep copies of data to ensure reliability.
- Error Correction:RAID 2, RAID 3, RAID 4 and RAID 5 use hamming code parity for error correction in data.
- Simultaneous I/O requests: RAID 0, RAID 4 and RAID 5 use the striping storage techniques hence support multiple I/O operations at the same time.
- Bulk data transfer:RAID 3 provides for quick bulk data transfers.
- Data security:Striping and continuous parity checks provide for high data security.
Disadvantages
- Cost: The cost of RAID systems is more than SLED systems.
- Data loss: The RAID systems that do not use mirroring are vulnerable to some data loss.
- Choice of RAID level:Given that there are so many RAID levels with each having some drawbacks and features of their it is a difficult choice as to what system can be used.
- Improper use:If RAID is not use properly, the overall performance of the system as a whole may decrease.
- Complex technology:RAID is a difficult to use architecture of data storage and requires skilled and proficient people to unlock the full potential of RAID.