Talk:Nested RAID levels

Linux RAID 10 driver

I've updated the Linux RAID 10 driver paragraph after reading the driver author's web page and examining the actual driver code. I've removed the line about RAID 10 on two disks and the block diagram as they are not standard RAID 10. Avernar 08:07, 2 January 2007 (UTC)

I've expanded the Linux RAID 10 section in the Proprietary RAID levels article to include the far layout so the block diagram is now there (but with three drives). Avernar 09:48, 2 January 2007 (UTC)

Edited the section on RAID 30

I removed the comment from the RAID 30 section which claimed the highest level of redundancy and performance for RAID 30, since it directly contradicts the statement in the preceding paragraph that, after one drive failure, all the other drives in the failed drive's cluster become a single point of failure. RAID 60, on the other hand, can afford to have half the drives in the entire array fail before data loss occurs. Gepard 12:30, 1 February 2007 (UTC)

Images and Diagrams

Please do not remove and images or diagrams. They're all there for a reason. The diagrams were added by various authors to prove a point. Eventually all the diagrams should be converted to images. Diagrams are easier to edit by most so that's what they start off as until someone with artistic talent updates them to an image.Avernar 15:53, 17 February 2007 (UTC)

Not a problem. Sorry about that. Koweja 17:47, 17 February 2007 (UTC)

RAID 51

There is a typo (or copy paste error) in RAID 10 and RAID 0+1 sections: "hybrid approaches such as RAID 0+1+5 (mirroring above single parity) or RAID 0+1+6 (mirroring above dual parity)." Mirroring above single parity is logically RAID 51 (this is consistence with main RAID article). I will correct this and add an external link to http://www.linux-tutorial.info about RAID. Kopovoi 15:31, 20 February 2007 (UTC)

RAID 10 definition

It appears that someone has got it wrong. This article, http://msdn2.microsoft.com/en-us/library/ms190764.aspx and others have RAID 10 the other way around. Which is right? 212.212.161.101 10:38, 30 April 2007 (UTC)mct

I would not put the question so sharp.

It is indeed the question of definition. As it is stated in [[1]]: "The difference between 0+1 and 1+0 might seem subtle, and sometimes companies may use the terms interchangeably." Or "Microsoft SQL Server 2000 High Availability": "Striped mirrors and mirrored stripes often confuse people, and manufacturers might call them RAID 10, RAID 0+1, RAID 1+1, RAID 01, and other terms. Work with your manufacturer to understand which one they actually implement for their disk subsystems." We can mention the situation in the article.

One can define mirror made of stripes to be RAID 0+1, meaning that first you apply stripe (raid 0) and then you apply mirror (raid 1). One can also call it RAID 10, translating directly "mirror of stripes" = "1 of 0" = "10".

Still, I would choose the definition from the site, where both RAID 10 and RAID 01 are mentioned, to be sure that the author is aware of the distinction. I would also prefer the link from hardware manufacturer whose product really support the both RAIDs. Kopovoi 12:55, 30 April 2007 (UTC)

There's further confusion in that it should be very simple to switch an array between 1+0 and 0+1 as no data needs to be moved to do the switch (the ondisk layout is the same). This generally should mean that only poor hardware supports both raid combinations but good hardware will be able to do anything the poor hardware can with their stripe and mirror layout. 86.13.76.46 (talk) 09:43, 24 June 2008 (UTC)

Inaccuracy in RAID 60 section

The section contains the following sentence:

 more than half of the disks must fail in the above example in order to lose data

If three disks from the same RAID 6 set fail, then all data is lost. Three is less than half of the disks. —Preceding unsigned comment added by 194.151.55.34 (talk) 15:45, 25 January 2008 (UTC)

RAID 00

Is RAID 0+0 possible? what would be the drawbacks and advantages? for example:

Hard1     Hard2     Hard3     Hard4
A1        A2        A3        A4
B1        B2        B3        B4
C1        C2        C3        C4
D1        D3        D4        D4

--83.183.127.178 (talk) 14:40, 14 June 2008 (UTC)

It's the same as plain RAID 0 across more disks, though working out what the strip size will be can be 'interesting' 86.13.76.46 (talk) 09:38, 24 June 2008 (UTC)

A note regarding edit by 87.194.157.28

For reference, that IP is mine (i.e. static), and I made that edit before I had an account. Feel free to delete this note.

--Elrebrin (talk) 14:26, 31 December 2008 (UTC)

Restrictive definition of RAID 0+1 and 1+0

At the lowest nested level, the sub-arrays are not limited to pairs of disks. It is perfectly valid to have for example, a RAID 1+0 array using mirrored sets of 3 or more disks. Can this be somehow incorporated into the article? --Spook ^{(my talk | my contribs)} 06:20, 5 February 2009 (UTC)