Re: i386 Installer questions: MBR slices, ext2fs root, bootblock location

[Greg Troxel <gdt%lexort.com@localhost>]

Nutchanon Wetchasit <xwindows%xwindows.in.th@localhost> writes:

>  1. Is it possible to install NetBSD root filesystem _directly_
>     as a MS-DOS disklabel slice (primary or logical type)
>     without having to create a nested disklabel like FreeBSD did?
>
>     ^ The installer itself apparently said that the nested disklabel
>       was required [1]; but I would like to ask for sure whether
>       it was an absolute requirement, especially _if_ NetBSD
>       was installed manually without using the installer.
>
>       And if the NetBSD disklabel was really required, was that an
>       installer-level (i.e. the TUI installer won't allow proceeding
>       in other way), kernel-level (i.e. the kernel won't find its root
>       without BSD disklabel), or bootloader-level limitation (i.e. the stock
>       bootloader won't read the file system without BSD diskabel)?
>
>     I have an unusual on-disk partitioning, and tinker with disks
>     and partitions at block level from time to time; so I would like to avoid
>     the complexity of nested partitions if doing so was possible.

I am not sure it is possible and it is definitely not a good idea.

If you use GPT, you can avoid all this.

The VM guest doesn't need to see the host partitioning; it can just have
space from your host LVM, and do GPT in that.

My advice is don't fight nested labels within a block that's hosted.  It
won't help you to win that at all.

>  2. Is it possible to install NetBSD in a manner which everything
>     (root, home, dev, usr, tmp, var, etc) were confined in a single
>     root filesystem, with *NO* swap space? If so, would it require completing
>     some parts of the installation outside of a TUI installer
>     in order to make it so?
>
>     Note that the single-root scheme is actually my preferred filesystem
>     scheme all of my past and current GNU/Linux systems in the last
>     20 years, for simplicity in block-level arrangement
>     and for any block-level intervention/tinkering I need or want to do. [2]

Yes that's fine.  I think you can do it with the installer.   Not even odd.

>  3. Is it possible to use Linux ext2fs filesystem type as a NetBSD
>     *root* partition? If it was, could it be partitioned/formatted/chosen
>     directly from TUI installer; or such partition had to be manually created
>     and formatted on command line (or from GNU/Linux system) beforehand,
>     then chosen as a root in the installer afterward?
>
>     If not, would it be okay to use Linux ext2fs as NetBSD home, usr, tmp,
>     and var? And would it okay for the `/home`, `/usr`, `/tmp`, and `/var`
>     on NetBSD root filesystem to be symlinks to other mounted filesystems?
>     (I understand that the installer itself likely won't allow doing this,
>     but I'll do so manually when needed)
>
>     ^ Note that I wanted to do this because I would like as much as possible
>       of my NetBSD install to be readable/writable from GNU/Linux
>       for diagnostics and data exchange reasons.

Maybe, but NetBSD's ext2fs code is not 100% ok and it is missing
features so you have to create any shared ext2fs from NetBSD.

>  4. Is there any inherent system (mainboard/pheripheral)-specific information
>     or driver binding/loading configuration that is recorded as a part of
>     installation process, that would make a NetBSD installation _not_ work
>     with other (NetBSD-compatible) computer?

No, unless you have to use userconfig at boot time.  The kernel has
drivers, and things are probed at boot.

>     I.e. if I installed NetBSD on one (NetBSD-compatible) computer
>     in a usual way, then unplug its hard disk and move it
>     to another (NetBSD-compatible) computer of the same CPU architecture
>     but different brand of mainboards and peripheral cards;
>     would the moved NetBSD instance still boot and use the new hardware
>     automatically? [3]

Yes, if an install would have succeeded on the new one.

[more later unless somebody else answers]