On Wed, Dec 09, 2009 at 11:10:35PM -0500, nixlists wrote: > On Wed, Dec 9, 2009 at 10:42 PM, Marco Peereboom <sl...@peereboom.us> wrote: > > It isn't identical because softraid does not initialize raid 1 because > > it doesn't matter. So all written data is the same but areas where the > > volume has not been written before will vary on the individual disks. > > What happens if the written data is not the same for some reason (and > what's the likelihood of this happening)? How does the OS and fsck > behave in this case?
There is no way to quantify that. You are the one that needs to calculate the odds and see if they meet your expectations. No telling on fsck/OS; could be from silent data corruption to looking at a ddb prompt. > > > Kind of. The short is that you can't guarantee this. Even if you > > detect that 2 areas that should have been the same but are not you > > really have no way of figuring out which one is correct (if any). > > > Note: this whole story is different with RAID 5 & RAID 6. > > Parity helps quite a bit, heh? Dramatically.
