Re: portable USB disk installation

[Malcolm Herbert <mjch%mjch.net@localhost>]

On Sun, Oct 06, 2019 at 03:28:39PM +0100, David Brownlee wrote:
|On Sun, 6 Oct 2019 at 14:03, Rhialto <rhialto%falu.nl@localhost> wrote:
|> On Sun 06 Oct 2019 at 13:46:03 +0200, orr721 wrote:
|> > Is there some way how to make the installation disk number
|> > agnostic?
|>
[ snip ]
|>
|> So instead of '/dev/sd0a' you would use 'ROOT.a', etc.

huh ... when did this become available? that's pretty neat

continuing on with this feature, how does this interact with something
like /etc/dumpdates? does the root device name remain the same? dump
will rely on the device name to keep track of which level of dump is
required next ... if it changes, you might still need the RAIDFrame
trick below

|If you need to do this on older NetBSD systems you can setup a single
|element autoconfiguring raidframe device (eg raid6) and have root on
|raid6a - I've done that one NetBSD7 & 8. (If you are running a new
|enough release to have ROOT though, don't bother faffing with raidframe
|for this :-p)|

yes, I was about to chime in with this response as I do exactly this on
some of my older instances, but you beat me to it ... :)

also - I've recently discovered a bunch of disks with old installs of
NetBSD on them from some of my hosts where either the hardware died or
the disk developed dud sectors[1] ... modern Linux doesn't understand
RAIDFrame or ffs, but you can easily convince VirtualBox to create a
.vmdk disk which references the appropriate disk device[2], create an
appropriate VM shell and then boot directly off the USB disk - I mention
this because it might be useful for someone in a pinch if they have
a box which has fallen over and no other *BSD hosts handy to plug it
into[3]

Regards,
Malcolm

[1] in the case of the disk with bad sectors, the host couldn't complete
an fsck so I did need to use ddrescue to do a block-level copy of what
was recoverable first, but otherwise it was the same process

[2] not a copy, think more a symlink to it - for example:

  vboxmanage internalcommands createrawvmdk \
    -rawdisk /dev/sdd1 -filename foo.vmdk

see https://www.virtualbox.org/manual/ch09.html#rawdisk

[3] be aware of RAIDFrame auto-numbering if you do this to a NetBSD host
that uses it, because the host sees it first before VirtualBox gets a
chance to ...

-- 
Malcolm Herbert
mjch%mjch.net@localhost