Question

What is RAID storage technology? Describe in detail at least 4 different types of RAID

Answer 1

RAID is defined as redundant array of independent disks. RAID storage uses multiple disks to improve storage capacity, to provide fault tolerance and improve overall performance. It basically allows to store redundantly in multiple paces in contrast to earlier storage system where only single disk is used for storage.

Based on the different architectures called levels, RAID storage devices are categorised. Each level corresponds to a desired balance between performance and fault tolerance.

Below are the different types of RAID Storage :-

1. Level 0 :- Striped disk array without fault tolerance. This provides data stripping ie. spreading out blocks of each file across multiple disk drives ; but no redundancy . This definitely improves performance but there is no fault tolerance.

2. Level 1:- Mirroring and duplexing .This architecture level provides disk mirroring..i.e. twice the read transition rate of single disks same write transaction rate as single disk

3. Level 2: Error Correcting coding. It consists of a bit level stripping. All disk spindle rotation is synchronized and data is tripped such that each sequential bit is on a different drive. This level is mainly of historical significance

4. level 3:- This consists of byte level stripping with dedicated parity . The main advantage of RAID 4 over 2 and 3 is the parallelism. In RAID 4 one read operation does not have to spread across all data drives. As a result, more I/O operations can be executed in parallel, improving the performance of small transfers.