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A RAID 0 array of n drives provides data read and write transfer rates up to n times as high as the individual drive rates, but with no data redundancy. As a result, RAID 0 is primarily used in applications that require high performance and are able to tolerate lower reliability, such as in scientific computing [5] or gaming.
Nested RAID levels, also known as hybrid RAID, combine two or more of the standard RAID levels (where "RAID" stands for "redundant array of independent disks" or "redundant array of inexpensive disks") to gain performance, additional redundancy or both, as a result of combining properties of different standard RAID layouts.
RAID 5E, RAID 5EE, and RAID 6E (with the added E standing for Enhanced) generally refer to variants of RAID 5 or 6 with an integrated hot-spare drive, where the spare drive is an active part of the block rotation scheme. This spreads I/O across all drives, including the spare, thus reducing the load on each drive, increasing performance.
RAID 6 requires a minimum of four disks. As with RAID 5, a single drive failure results in reduced performance of the entire array until the failed drive has been replaced. [11] With a RAID 6 array, using drives from multiple sources and manufacturers, it is possible to mitigate most of the problems associated with RAID 5.
Linux supports Matrix RAID and Rapid Storage Technology (RST) through device mapper, with dmraid tool, for RAID 0, 1 and 10. And Linux MD RAID, with mdadm tool, for RAID 0, 1, 10, and 5. Set up of the RAID volumes must be done by using the ROM option in the Matrix Storage Manager, then further configuration can be done in DM-RAID or MD-RAID. [10]
geom_raid5 is a storage module created for the FreeBSD operating system. It facilitates RAID5 functionality without the need of a hardware RAID controller.. geom_raid5 allows storage of large amounts of data to be protected against disk failure, while providing good throughput performance.
NCQ can negatively interfere with the operating system's I/O scheduler, decreasing performance; [8] this has been observed in practice on Linux with RAID-5. [9] There is no mechanism in NCQ for the host to specify any sort of deadlines for an I/O, like how many times a request can be ignored in favor of others.
IBM Variable Stripe RAID is a patented [29] highly granular RAID 5 type data protection arrangement implemented across each set of 10 flash chips in the system. IBM FlashSystem 900, 840, 820, and 720 products also include a second layer of RAID 5 implemented within the data distribution logic at the system level, providing "two-dimensional ...