Understanding RAID Concepts and Levels
disk arrays achieve highest transfer rates and performance at the expense of fault tolerance.
Distributed Parity. Parity works in combination with striping on RAID 5 and RAID 50. Parity information is written to each of the striped drives, in rotation. Should a failure occur, the data on the failed drive can be reconstructed from the data on the other drives.
Hot Spare. A single drive that is not used for user data, but rather as an extra drive that is online and available to automatically take the place of any drive that fails in a redundant unit. Used with RAID 1, 5, 10 and 50.
Hot Swap. The process of exchanging a drive without having to shut down the system. This is useful when you need to exchange a degraded drive. It is also useful if you want to add disk drives to configure into a unit without shutting down the system first.
Configurations Available with the 3ware RAID Controller
The following RAID levels and configurations are available for drives attached to a 3ware RAID controller:
RAID 0. Provides striping, but no mirroring or redundancy of any kind. Striped disk arrays achieve high transfer rates because they can read and write data on more than one drive simultaneously. The stripe size is configurable in 3ware BIOS Manager (3BM). Requires a minimum of two drives.
When drives are configured in a striped disk array, large files are distributed across the multiple disks using RAID 0 techniques.
Striped disk arrays give exceptional performance, particularly for data intensive applications such as video editing, computer- aided design and geographical information systems.
RAID 0 arrays are not fault tolerant; the loss of any drive results in the loss of all the data in that array, and can even
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