Re: Beating a dead horse

[Robert Elz <kre%munnari.OZ.AU@localhost>]

    Date:        Wed, 25 Nov 2015 13:20:14 -0700 (MST)
    From:        Swift Griggs <swiftgriggs%gmail.com@localhost>
    Message-ID:  <alpine.NEB.2.11.1511251308190.10284%swift-m83.parsec.com@localhost>

  | I wonder if the same is true for LVM?

No idea.   I thought it should be easy enough to test, so I just tried
that ...  unfortunately, I cannot work out (with 5 minutes of research!)
how to make it work, so no luck...

lvm wasn't on my radar - while it seems to do a lot, encryption doesn't
appear to be included.  My 4k sector drive is a USB removable, which is
the kind of thing that mandates encryption, so I want/need cgd on it.
ANything else after that is just frills...  (there's just one of them,
now anyway, so raid etc isn't important, and it is mostly for backups,
so doesn't need lots of small data volumes, just one big place to
put dump files...)


First problem with testing lvm is that amd64 GENERIC (and consequently my
cut down version) doesn't have "pseudo-device dm" in it, so llvm isn't going
to work there at all.   That's easy to fix of course, so I did that.

But after that, I couldn't figure out how to make

	lvm pvcreate dk13

work, it just said (something like, paraphrasing, that system isn't
running any more) "invalid device or disabled by filtering"

Initially dk13 was of type "cgd" in the GPT label.   I wasn't sure what
to make it for LVM, there doesn't seem to be a NetBSD UUID for that,
so I tried setting it to linux-lvm on the assumption that would work.
Changed nothing.

I was using a current kernel (7.99.21) from a couple of weeks ago.
I can upgrade to a newer one if that is likely to help (but I doubt it).

That's where I gave up.   If anyone has a recipe I can follow to create
an lvm volume on a GPT partitioned drive (I *will not* revert to MBR or
disklabel - those are "so 20th century") and can tell me just how to run a
test, I'm willing to try, anytime in the remainder of this week.

After that, I'm going to be away from my 4k sector drive for all of
December, so I won't be testing lvm, or working on cgd at all.   If anyone
else wants to fix cgd for 4k sector size discs during Dec, please go ahead.
So far all I've been doing is investigating, and thinking, I have nothing
productive to share yet...

  | Since it's relatively new, perhaps 
  | some of these issues were worked out in a more "modern" way that would 
  | properly take advantage of the NetBSD-7 kernel.

The kernel does some stuff right for non 512 byte sector disks, but still
does lots wrong.   It is still a mess in this area.

kre