RAID Disc System
In configurations RAID-5 treatment to the disk occurs only when it read / record
information about parity or data. As a result, RAID-5 is better than RAID-3,
productivity. In practice, productivity RAID-5 can sometimes reach or even
surpass the performance odnodiskovyh systems. This increased productivity, of
course, depends on many factors, including how RAID array is implemented and
what possibilities there are of the server operating system. RAID-5 is also the
highest among all standard implementations of RAID level data integrity, as both
data and parity information on alternating enrolled. Because RAID-5 uses a
bundle of blocks rather than bits, synchronization speed gives no advantages in
productivity.
Some manufacturers have added to their expansion systems RAID-5. One such
extension is the availability of a built-in disk array; hot pool; (hot-spare).
If a crash occurs drive, the drive from the hot pool immediately replaces
emergency disk and copies the data themselves through their restoration of
parity in the background. But remember that the restoration disk RAID-5 has a
serious fall in the performance of your server. (For more information on the
disk with; hot replacement, and, hot redundancy; see in the box; Hot; functions
discs;.) RAID systems can be arranged with the help of downloaded on the server
and uses for his work on the processor, and when specialized assistance RAID
controller. Programmno-realizovannye RAID systems take a significant portion of
system CPU resources, as well as system memory, which greatly reduces the server.
Software RAID system sometimes included in the functions of the operating system
(as is done in Microsoft Windows NT Server), or from third supplement suppliers
(as has been done in NetWare and Macintosh operating system).
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