RAID 1 is mirroring one disk with a bit-by-bit copy of another disk.
This is by convention only: the marginal utility of an additional disk drops rapidly, therefore no COTS solutions above 2 disks. I run 3-disk RAID-1 arrays, exactly for correcting errors on n-1 disks (also, if one disk in a 2-disk array fails, the other one practically tends to fail soon after, whatever the reason - from suddenly bearing the whole load? from being similar in age? from being from the same production batch?).
More-disks RAID 1 is merely impractical for archival, with its costly requirement for disk redundancy: it kind of works, but it's not the right tool for the job (as opposed to availability for currently-used data).
However, your point with "no detection of silent corruption" has merit. I suggest an addition to the RAID 1 paragraph:
While it's possible to have multiple disks in a RAID 1 array, you are paying a multiple of the storage price, with the same storage capacity as with a single disk, without a commensurate increase in resilience. In other words, not very efficient.
This is by convention only: the marginal utility of an additional disk drops rapidly, therefore no COTS solutions above 2 disks. I run 3-disk RAID-1 arrays, exactly for correcting errors on n-1 disks (also, if one disk in a 2-disk array fails, the other one practically tends to fail soon after, whatever the reason - from suddenly bearing the whole load? from being similar in age? from being from the same production batch?).
More-disks RAID 1 is merely impractical for archival, with its costly requirement for disk redundancy: it kind of works, but it's not the right tool for the job (as opposed to availability for currently-used data).
However, your point with "no detection of silent corruption" has merit. I suggest an addition to the RAID 1 paragraph: