Does anyone have experience with applying deduplication to shares that contain Windows system backups?
Does it save enough space to make it worth doing?
Are there any gotchas?
I think it matters if you are using backup software which creates a backup file, in that case I would say that deduplication will not help.
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That depends whether you have enough backups to have enough potential duplicates…
Deduplication is a resource hog. For a start, you only have half the amount of RAM which would be considered as necessary to even begin to think about dedup—yes, it’s THAT bad.
RAM requirements may be alleviated with a special vdev on SSDs, but then you’d need a 3-way mirror to match the redundancy of a raidz2 pool and I suspect that you have other uses for the various PM893. A persistent L2ARC would help with mostly-WORM use case, which regular backups from Windows clients is likely not—more “write everytime there is a change and read once in a blue moon when restoring”.
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Wild ass guess, If you can guarantee a 5:1 reduction then perhaps it makes sense.
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Yeah, based on what you guys have said and on what I read in the ZFS books I have decided not to De-Dupe for the foreseeable future.