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Re: LVM RAID5 with missing disk?

Bob Proulx a écrit :
> Pascal Hambourg wrote:
>> Bob Proulx a écrit :
>>> I favor RAID6's extra redundancy for more safety but I
>>> still use RAID1 too.
>> RAID 1 can provide as much or more redundancy than RAID 6.
>> RAID 1 on 3 disks provides as much redundancy as RAID 6.
>> RAID 1 on 4 disks provides more redundancy than RAID 6 (but half the
>> usable space).
> Do you have any articles or blogs or postings you have written that
> would summarize raid alternatives?  I would enjoy reading whatever you
> have written on the subject.  Or if you recommended other references.

There is no need to write anything new about that subject. All is
already available on Wikipedia, raid.wiki.kernel.org and so on.

What I wrote above is simply derived from the definition of the RAID
levels :
A RAID 1 array of N disks provides fault tolerance for up to N-1 disks.
A RAID 6 array provides fault tolerance for up to 2 disks.
N-1 (RAID 1 fault tolerance) >= 2 (RAID 6 fault tolerance) if N >= 3

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