About RAID
What is RAID? Originally, as envisaged in 1987 by Patterson, Gibson and Katz from the University of California in Berkeley, the acronym RAID stood for a "Redundant Array of Inexpensive Disks". In brief...
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RAID 0 (Striping)
RAID 0 provides capacity and speed but not redundancy (so it is AID rather than RAID). Data is striped across the drives with all of the performance benefits that gives, but if one drive fails the...
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RAID 1 (Mirroring)
RAID 1 is often used for the boot devices in servers or for critical data where reliability requirements are paramount. Usually 2 hard disk drives are used and any data written to one disk is also...
View ArticleRAID 2, RAID3 & RAID 4
RAID levels 2, 3 and 4 were proposed when RAID was first postulated as a method, but have been either little used or else have fallen out of favour. RAID levels 0, 1 and 5 seem to "cover all of the...
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RAID 5
RAID 5 stripes at the block level but does not use a single dedicated drive for storing parity. Instead, parity is interspersed within the data, so after each sequence of data blocks there is a block...
View ArticleRAID 6
RAID 6 stripes at the block level and then stores two blocks of parity, one more than for RAID5. Parity is interspersed within the data, so for each run of data blocks there are two blocks of parity...
View ArticleRAID 10
RAID 10 is a "nested" RAID level, the "10" being a reflection of RAID 10 being RAID 1+ RAID 0 (aka RAID 1+0). The general principle of RAID is that multiple disks are used to create a single disk,...
View ArticleRAID 0+1
RAID 0+1 is, like RAID 10, a nested RAID or a combination of different RAID implementations. RAID is a method of using multiple hard drives to either create a larger hard drive, to add protection...
View ArticleRAID 50 (RAID 5+0)
RAID 50 is a nested or hybrid RAID level. Whilst RAID was originally envisaged as a method of using multiple hard disk drives to create a larger single "disk", to add some data security, or a...
View ArticleRAID 51 (RAID 5+1)
RAID 51 is a hybrid of RAID 5 and RAID 1, it is a RAID 1 mirrored array where the composite elements are not individual hard disk drives but each is a RAID 5 array. The other way of looking at RAID51...
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