On Sat, Mar 10, 2018 at 03:55:25AM +0100, Christoph Anton Mitterer wrote: > Just wondered... was it ever planned (or is there some equivalent) to > get support for btrfs in zerofree?
Do you want zerofree for thin storage optimization, or for security? For the former, you can use fstrim; this is enough on any modern SSD; on HDD you can rig the block device to simulate TRIM by writing zeroes. I'm sure one of dm-* can do this, if not -- should be easy to add, there's also qemu-nbd which allows control over discard, but incurs a performance penalty compared to playing with the block layer. For zerofree for security, you'd need defrag (to dislodge partial pinned extents) first, and do a full balance to avoid data left in metadata nodes and in blocks beyond file ends (note that zerofree doesn't do this on traditional filesystems either). Meow! -- ⢀⣴⠾⠻⢶⣦⠀ ⣾⠁⢠⠒⠀⣿⡁ A dumb species has no way to open a tuna can. ⢿⡄⠘⠷⠚⠋⠀ A smart species invents a can opener. ⠈⠳⣄⠀⠀⠀⠀ A master species delegates. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
