Memory for disk arrays
This scheme is designed for storage applications, where the data was originally
divided into small blocks, so there's no need for additional but they split.
RAID 4 is a good solution for file servers, with the information to which it
reads and essentially rarely recorded. The scheme has low storage cost-heavy,
but its implementation is complex as the restoration of data on failure.
Advantages: -- very high speed reading large amounts of data; -- high
productivity with high-intensity reading data queries; -- small overhead for the
implementation of redundancy. Disadvantages: -- quite a complicated
implementation; -- very low productivity in data recording; -- complex data
recovery; -- Low-speed data reading with a small amount of single queries; --
asymmetry performance on reading and writing. iii. RAID 5 - tolerant array of
independent disks distributed entirely clear (Independent Data disks with
distributed parity blocks) RAID Level 5 - it is tolerant array of disks with
distributed storage contracts trolnyh amounts . Blocks of data and checksums,
which are calculated in the same way as in RAID 3, cyclically recorded on the
disks array, that is, there is no dedicated disk for the storage of information
on the amounts of control. In the case of a RAID 5 array drives all have the
same size, however, the total capacity of the distribution Koch subsystem
available for writing, it becomes less exactly on the same CD.