Re: vndcompress and wedges

On Wed, Feb 26, 2020 at 11:35 bch <brad.harder%gmail.com@localhost> wrote:

On Wed, Feb 26, 2020 at 09:47 bch <brad.harder%gmail.com@localhost> wrote:

Hello.

I’m trying to make a copy of a disk I have before I newfs it to start from a clean slate.

The machine in question boots (but has an issue w /lost+found that fsck cannot fix). The 1tb ssd is setup w 3 wedges: 1st for efi, 2nd for NetBSD/ffs, 3rd for swap.

I boot w a NetBSD 9 install iso (USB key), and I can mount the internal disk /dev/dk1 and see the familiar contents. I have an external USB disk that I’m using to store an image to.

With the dk1 unmounted, I ran:

# </dev/rdk1 progress -l 939413388k vndcompress -c -k 256 -l 939413388k /dev/stdin /mnt/home/bch/myimg.imz

...which ran (for a long time) apparently without error.

I associate the img w and vnd device:
# vndconfig -z vnd0 /mnt/home/bch/myimg.imz

Then try mounting (vnd0a or vnd0d) and get “incorrect superblock” errors. What am I doing incorrectly? disklabel reports ‘a’ as fstype 4.2BSD and ‘d’ as unused, which is similar to what I read here:
http://netbsd.2816.n7.nabble.com/Using-cloop2-images-td66421.html#a66423

Help?

Further: if I dd(1) a section of either vnd0a or d, the chunk reports as a DOS/MBR boot sector, which happily mounts with -tmsdos, yielding an empty mountpoint (eg: it mounts, but navigating there shows there are no contents). The compressed img I’ve got is 73G of what I thought was the NetBSD FFS wedge...

Further still, if I open the dd(1) creates subsection w a binary editor, I can indeed search through the data and see names of custom kernels I’ve created in the past. Is it a case of some MBR “junk” preceding the wedge snapshot I took, and need to seek ahead to mount the img?