Looking for some expert advice. I read with interest the "Recovering a
damaged RAID" wiki at:
https://raid.wiki.kernel.org/index.php/Recovering_a_damaged_RAID
Summary is I have a Synology DS916+ NAS enclosure which was working
properly and was trying to upgrade a set of drives from 4TB drives to
10TB drives. The issue is the 10TB drives were Amazon Warehouse Deals
and they seemed to be used with raid data on them. My complete saga is
posted here:
https://www.reddit.com/r/DataHoarder/comments/aws9iv/btrfs_shr_rookie_mistake_dd_bs1m/
The end result is I violated the fundamental rule of debug... don't do
anything to a live array.
I ended up doing zeroing the first 1M sectors of my live /dev/md3
array. :homer doh:
# dd if=/dev/md3 of=<some useful filename> bs=1M count=1
I don't know much about raid; much less how Synology set up the arrays
so I basically looking for crawl, walk, run type advice in determining
the best course of action on how to repair.
I *did* make a backup copy of the 1M sectors before I did the dd...
BUT; I didn't practice smarts and copy the backup to a usb drive
before doing the zero wipe. Additionally; while I did back up some
critical data... it would be quiet painful to restore that data... and
there would be data loss.
My questions are still pretty basic. I'm looking for basic information
as to how to start repairing this mistake. Ideally I'd like to somehow
restore enough functionality to pull off the "backup" file then use
that backup file to restore ?complete? access to the array.
Is this even possible?
Side note; I do have a copy of ONE of the member drives from the
array. At the time the raid was zero-ed... it was physically
disconnected from the system in a antistatic bag. IF so, Could that be
used to "rebuild" the first 1M?
Is there a backup copy mbr/partitions somewhere I could use to restore?
Finally; I posted a bunch of outputs on reddit when I was getting
help... but the experts disappeared.
https://www.reddit.com/r/DataHoarder/comments/aws9iv/btrfs_shr_rookie_mistake_dd_bs1m/ehp5o2z
I'm happy to report the relevant data here if it's helpful.
John
