Re: dump to cgdNb device

[Alexander Nasonov <alnsn%yandex.ru@localhost>]

Taylor R Campbell wrote:
> Just to double-check (since I am likely to make this mistake myself!),
> you're not using a random-keyed cgd, right?  Random-keyed cgd is great
> for swap while the key is in memory but not so great for dump after
> rebooting!

I have both types but the one I was testing was definitely with a
persistent key.

> Does strings(1) on /dev/rcgd1b show anything vaguely meaningful?

Yes, I see this string:

NetBSD 7.99.30 (CGDDEBUG) #0: Thu Jun 16 19:40:27 BST 2016
        alnsn@neva:/home/alnsn/netbsd-current/clean/src/sys/arch/amd64/compile/obj/CGDDEBUG

This is the kernel I was running. The disk was initially filled
with random bits and CGDDEBUG kernel didn't exist back then.

> Hmm...  I might have caused your dump to scribble all over another
> part of the disk, by not adjusting the blkno before passing it along
> to bdev_dump.  I'm not sure about this -- but the blkno adjustments
> certainly need to be reviewed.

I don't see any problem after reboot. I cat'ed all files in neighbour
partitions (496M and 3G) to /dev/null and I don't see any error. There
aren't full, though. One if about 50% full, the other is 23% full.

Alex