On 24/07/12 07:31, Drew wrote: > Been mulling this problem over and I keep getting hung up on one > problem with ECC on a two disk RAID1 setup. > > In the event of silent corruption of one disk, which one is the good > copy? > > It works fine if the ECC code is identical across both mirrors. Just > checksum both chunks and discard the incorrect one. > > It also works fine if the ECC codes are corrupted but the data > chunks are identical. Discard the bad checksum. > > What if the corruption goes across several sectors and both data & > ECC chuncks are corrupted? Now you're back to square one. I know I'm a bit late to this discussion, and I know very little about the code level/etc... however, I thought the whole point of the checksum is to determine that the data + checksum do not match, therefore the data is wrong and should be discarded. You would re-write the data and checksum from another source (ie, the other drive in RAID1, or other drives in RAID5/6 etc...). ie, it should be treated the same as a bad block / non-readable sector (or lots of unreadable sectors....) Regards, Adam -- Adam Goryachev Website Managers www.websitemanagers.com.au -- 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
