5-Understanding RAID
RAID 1 (Disk Mirroring)
RAID 1, also known as “disk mirroring”, distributes duplicate data simultaneously to pairs of disk drives.
Pros: RAID 1 offers extremely high data reliability as all the data is redundant. If one drive fails, all data (and software applications) are preserved on the other drive.
Read performance may be enhanced as the array controller can access both members of a mirrored pair in parallel.
Cons: RAID 1 volume requires double the raw data storage capacity Performance penalty when compared to writing to a single disk.
RAID 10
RAID 10 is a combination of RAID 0 and RAID 1, combing striping with disk mirroring. RAID Level 10 combines the fast performance of Level 0 with the data redundancy of Leve1 1. In this configuration, data is distributed across several disk drives, similar to Level 0, which are then duplicated to another set of drive for data protection. RAID 10 provides the highest read/ write performance of any of the Hybrid RAID levels, but at the cost of doubling the required data storage capacity.
Pros: Fastest read/write performance of any of the Hybrid RAID levels
High data reliability as all the data is redundant
Cons: Requires double the raw data storage capacity
RAID 5
RAID 5 is sometimes called striping with parity at byte level. In RAID 5, the parity information is written to all of the drives in the subsystems rather than concentrated on a dedicated parity disk. If one drive in the system fails, the parity information can be used to reconstruct the data from that drive. All drives in the array system can be used to seek operation at the same time, greatly increasing the performance of the RAID system. RAID 5 is the most often implemented RAID algorithm in RAID arrays.
Pros: Very good general transfer performance
Fault tolerant
Cons: Can be slow at large size file transfers
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