December 28th, 2009

So 4K sector drives are coming, but are they safe?

Journaling in recent filesystems should prevent data corruption during powerfail, and it seems to work with 512b sector drives these days. Now... of course 4K can emulate 512b sectors using RMW cycle in common case, but can they also provide some guarantees over powerfail? 3.5KB of junk scribbled to adjacent partition would be pretty bad news.

Now... I do not think 512b sector drives "officially" provide any guarantees on powerfail behaviour; but they seem to behave sanely. That's good more reason to avoid 4K drives: I suspect the answer will be "we never guaranteed anything during powerfail".