[Discuss] Redundant array of inexpensive servers: clustering?

[Richard Pieri]

markw at mohawksoft.com wrote:
> I currently work at a fairly high end deduplicated backup/recovery system
> company. In a deduplicated system, a "new" backup should not ever be able
> to trash an old backup. Period. Only "new" data is added to a deduplicated
> pool and old references are untouched. Old data is not over-written. You
> can see this behavior in almost any deduplication strategy, including
> Windows NTFS and ZFS.

You're missing the point.

Say you have disk A and disk B. Every block written to A is replicated to B.

Data on blocks on A are damaged.

Damaged data blocks on A are replicated to B.

B is now a 1:1 replica of the trashed data on A.

-- 
Rich P.