Linked by Thom Holwerda on Mon 18th Jan 2010 16:57 UTC, submitted by wanker90210
Hardware, Embedded Systems ACM's latest journal had an interesting article about RAID which suggested it might be time for triple parity raid. "How much longer will current RAID techniques persevere? The RAID levels were codified in the late 1980s; double-parity RAID, known as RAID-6, is the current standard for high-availability, space-efficient storage. The incredible growth of hard-drive capacities, however, could impose serious limitations on the reliability even of RAID-6 systems. Recent trends in hard drives show that triple-parity RAID must soon become pervasive."
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RE[4]: RAID Z
by CodeMonkey on Tue 19th Jan 2010 16:29 UTC in reply to "RE[3]: RAID Z"
CodeMonkey
Member since:
2005-09-22

I can use a on-board RAID5 controller (read: soft-RAID) built array and move it from Windows to Linux and back, it's a standard.


Having a driver for a particular piece of hardware in 2 OS's does not make a standard. Common, sure, but standard, no. Now, if you could build the RAID 5 array on one brand and version of controller and the use that same array with a different brand and version controller, that would be more standard like.

Various RAID levels aren't like a standards spec to follow, more like an abstract description of an algorithm.

Let's say RAID5 is like a V6 engine in a car:

V6 = Use 6 cylinders arranged in a 2x3 V configuration.
There's no reason to expect a Honda V6 to fit in place of a Ford V6. Just because they're both a V6 doesn't make V6 a spec standard, just a common way to design an engine.

RAID5 = use 1 disk worth of parity information distributed and staggered across the entire array.
There's no reason to expect a RAID5 array built with an Adaptec controller to plug right in and work in place of an LSI built RAID5 array with an LSI controller. Just because they're both a RAID5 array doesn't make RAID5 a spec standard, just a common way to build a disk array.

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