On Mon, Dec 14, 2015 at 1:04 AM, Qu Wenruo <quwen...@cn.fujitsu.com> wrote: > > > Chris Murphy wrote on 2015/12/14 00:24 -0700: >> What is a full disk dump? I can try to see if it's possible. > > > Just a dd dump.
OK, yeah. That's 750GB per drive. >t won't be an easy > thing to find a place to upload them. Right. I have no ideas. I'll give you the rest of what you asked for, and won't do the rw mount yet in case you need more. > Got the result, and things is very interesting. > > It seems all these tree blocks (search by the bytenr) shares the same crc32 > by coincidence. > Or we won't be able to read them all (and their contents all seems valid). > > > I hope if I can have some raw blocks dump of that bytenr. > Here is the procedure: > $ btrfs-map-logical -l <LOGICAL> -n 16384 -c 2 <DEVICE1or2> > mirror 1 logical <LOGICAL> physical XXXXXXXX device <DEVICE1> > mirror 2 logical <LOGICAL> physical YYYYYYYY device <DEVICE2> Option -n is invalid, I'll use option -b. ##btrfs fi show has this mapping, seems opposite from btrfs-map-logical (although it uses the term mirror rather than devid). So I will use devid and ignore mirror number. /dev/sdb = devid1 /dev/sdc = devid2 # btrfs-map-logical -l 714189357056 -b 16384 -c 2 /dev/sdb checksum verify failed on 714189357056 found E4E3BDB6 wanted 00000000 checksum verify failed on 714189357056 found E4E3BDB6 wanted 00000000 checksum verify failed on 714189357056 found E4E3BDB6 wanted 00000000 checksum verify failed on 714189357056 found E4E3BDB6 wanted 00000000 mirror 1 logical 714189357056 physical 356605018112 device /dev/sdc mirror 2 logical 714189357056 physical 3380658176 device /dev/sdb # btrfs-map-logical -l 714189471744 -b 16384 -c 2 /dev/sdb checksum verify failed on 714189357056 found E4E3BDB6 wanted 00000000 checksum verify failed on 714189357056 found E4E3BDB6 wanted 00000000 checksum verify failed on 714189357056 found E4E3BDB6 wanted 00000000 checksum verify failed on 714189357056 found E4E3BDB6 wanted 00000000 mirror 1 logical 714189471744 physical 356605132800 device /dev/sdc mirror 2 logical 714189471744 physical 3380772864 device /dev/sdb > > $ dd if=<DEVICE1> of=dev1_<LOGICAL>.img bs=1 count=16384 skip=XXXXXXX > $ dd if=<DEVICE2> of=dev2_<LOGICAL>.img bs=1 count=16384 skip=YYYYYYY > > In your output, there are 12 different bytenr, but the most interesting ones > are *714189357056* and *714189471744*. dd if=/dev/sdb of=dev1_714189357056.img bs=1 count=16384 skip=3380658176 dd if=/dev/sdc of=dev2_714189357056.img bs=1 count=16384 skip=356605018112 dd if=/dev/sdb of=dev1_714189471744.img bs=1 count=16384 skip=3380772864 dd if=/dev/sdc of=dev2_714189471744.img bs=1 count=16384 skip=356605132800 Files are attached to this email. -- Chris Murphy
dev2_714189471744.img
Description: application/raw-disk-image
dev2_714189357056.img
Description: application/raw-disk-image
dev1_714189471744.img
Description: application/raw-disk-image
dev1_714189357056.img
Description: application/raw-disk-image
