It is also worth saying that this has wandered way off topic. The comment about parity rebuild yadda yadda was an aside to the real meat: a drive replace facility that uses very efficient mirroring for >99.9% of the disk rebuild and parity for the <0.1% where a read-error occured. Hmm, it occurs in the event of a highly dodgy failed drive then maybe it could do >99.9% recovery from parity and in the event of a failure from one of the remaining drives, it could attempt a read from the dodgy disk. David Lethe wrote: > Sorry about rant .. but it got to me finally, where people keep posting > how S.M.A.R.T. seems > to be this all-knowing mechanism that tells you what is wrong with the > disk and/or where the > bad blocks might be. It isn't. No, but I run long self-tests on a weekly basis and when it tells me I have a bad block I can examine further; attempt a re-write; run another long test and see if it comes back clean. David Lethe also wrote: > As original poster wanted to just use SMART to factor in known bad > blocks on a rebuild, then you can see that there > Is no viable option unless you already have a full list of known bad > blocks. You have to find bad blocks as you > just read from them as part of the rebuild for these types of disks). I did say force a re-write of SMART identified badblocks using parity calculated values. and that was innacurate. I should have said something like: when SMART identifies a bad block then force a re-write using parity calculated values. I appreciate that SMART isn't that smart - but it has a lot of value way down here below the top-end enterprise systems. David -- "Don't worry, you'll be fine; I saw it work in a cartoon once..." -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
