On Tue, Jul 26, 2016 at 4:59 PM, David C. Rankin <drankinatty@xxxxxxxxxxxxxxxxxx> wrote: > On 07/26/2016 05:10 PM, Phil Turmel wrote: >> You won't be able to re-add sdd because as Chris said, "fixing" the >> primary GPT broke mdadm's superblock. After zeroing the beginning 4k of >> sdd, --add it to your array and let it rebuild. >> >> Phil > > Thanks Phil, what's the quickest way to zero the 4k, something like > > # dd of=/dev/sdd if=/dev/zero bs=1 count=4096 Yeah fine, or type the count= first so that if you accidentally hit return after you've completed typing if= and of= but before count= you aren't zeroing your drive very slowly but still too fast for a cancel to help save you. Just don't use bs=1 when you go to zero the backup GPT, because the sector values are predicated on 512 byte sectors, which happens to be dd's default bs= size. So if you use bs=1 without altering the seek value, you'll break something again. :-D -- Chris Murphy -- 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
