I believe btrfs has a "no COW" option. I'm not sure how much functionality you lose though - it's unlikely to support snapshots, and I have a feeling that it may disable checksumming as well.
Posted May 14, 2009 15:59 UTC (Thu) by masoncl (subscriber, #47138)
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The Btrfs nodatacow mode does disable checksumming, but it does not disable snapshots.
When you snapshot or create a clone of a nodatacow file, COW is enforced for the first write of each block after the snapshot, and then things go back to the regular nodatacow mode.