Re: NetBSD/Xen How to - suggestions

[Sarton O'Brien <bsd-xen%roguewrt.org@localhost>]

Hi John,

John Hayward wrote:
> Dear Netbsd Xeners,
>    I am in the process of set up xen on NetBSD.  I have a NetBSD-4.0 
> install and using xen3.
>    I ran into a few issues in the process following the How to:
>
> 1) When setting up grub it mentions putting the menu.lst in /grub
>    I also needed to (as mentioned in the installing with raid link at the
>    bottom of the NetBSD/Xen How to):
> ====
>    GRUB setup
>
> # mkdir /grub
> # cp -p /usr/pkg/lib/grub/i386-/* /grub
> ====
>    It might be nice to include this step.

This is only true if you have not already done a full grub-install.

Grub in it's self could be tackled in a varieties of ways, it all 
depends on the users experience or the howto they happened to google :)

I'd say grub is technically outside the scope of xen, but maybe a link 
to a netbsd orientated grub howto would be nice. Unfortunately the xen 
howto probably includes just enough grub info to confuse someone new.

> 2) It appears that the 4.0 generic and generic-mp kernels have a
>    Multiboot-enabled kernels (the default for NetBSD 4.x and above)
>    the "module --type=netbsd /..." did not work for me.  I needed
>    to remove the --type=netbsd on the kernel line for the items in
>    the menu.lst.  It is "exciting" when you have problems booting the
>    xen kernel (see item 3) then try to boot the "backup" generic
>    kernel and have that fail ;-)  I found about this flag in info
>    grub.

The xen howto never quite keeps up with the development state of xen 
under netbsd due to how quickly it changes. With an older xen/netbsd 
install this option may still be required. Once again though, this issue 
is still more grub related than xen ... maybe a grub howto would be 
beneficial ...

> 3) For some reason when I booted the xen.gz file as the kernel I got a
>    corrupted file error message.  I tried several times to rebuild this
>    file without success on booting.  If I uncompressed it and referenced
>    the uncompressed xen in the kernel line it booted without problem.
>    I don't know if there is something missing that while booting cannot
>    decompress the xen.gz or if there is a difference in how the
>    compression is done relative to decompression on boot.

And last ... but not least (as a lot of us have run into this one ... 
and a lot haven't) another grub issue.

This apparently stems from grubs inability to access the filesystem 
correctly. Don't ask me how.

If you have a small root partition (mine is 500MB) and you copy the 
compressed kernel there .... it may boot.

Apparently ffs version plays a part aswell. All my installs are default 
and dumpfs reports ffsv2 ... that may be part of the problem. 
Unfortunately this needs to be addressed by a grub dev.

Seeing as you had no actual xen issues, I'd say for the most part the 
howto was a success. My vote would be to remove grub to a seperate howto 
to detail potential issues under versions of netbsd ... and xen ... or 
just remove any detailed instructions pertaining to it, noting that 
additional grub configuration is required and btw, here's a few sample 
menu.lsts.

Either way, the howto did it's job, and you learned something along the 
way ;)

Sarton