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Re: LVM RAID5 with missing disk?



Hello,

Some mistakes in what you wrote.

Gary Dale a écrit :
>
> RAID 1 and RAID 5 are both immune to single disk 
> failures in their most common configurations (1 or more data disks with 
> 1 parity disk). RAID 10 is also immune to single disk failure but uses 
> half the disks for parity.

RAID 1 and 10 are just mirrors, they have no parity. I guess you mean
"redundancy".
RAID 5 does not use data disks and parity disks. Data and parity are
distributed among all disks in the array.
RAID 1 with N disks can survive N-1 disk failures.

> If you are concerned about availability, with 4 disks (the simplest RAID 
> 10 configuration)

Linux can use a special RAID 10 mode (mirror+stripe) with two or three
disks.

> with 6 disks, RAID 6 will give you double the capacity of 4 disks 
> or get you immunity to 3 disks failing.

RAID 6 can survive 2 disk failures regarless of the number of disks in
the array.


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