[9fans] Weird plan9 Xen DonU problems

[9fans] Weird plan9 Xen DonU problems

[Alan C. Fisher]

When running the plan9 installer in Xen, partdisk fails strangely:

init: starting /bin/rc
/bin/dossrv: serving #s/dos
dev 3 sector 18, write: 0, should be 4608
dev 3 sector 0, write: 0, should be 4608
dev 3 sector 18, write: 0, should be 4608
dev 3 sector 9, write: 0, should be 4608
dev 3 sector 4248, write: 0, should be 4608
use DMA for ide drives[yes]: no
rio: can't open display: initdisplay: /dev/draw/new: unknown device in # filename


failed to start rio.  you can start a text-based installation by running

	inst/textonly


init: starting /bin/rc
% inst/textonly
Sun Oct 2 02:16:21 BST 2011 Installation process started

--------------------------------------

Preparing menu...
The following unfinished tasks are ready to be done:
	configfs	- choose the type of file system to install
	stop	- save the current installation state, to be resumed later

Task to do [configfs]:

--------------------------------------
You can install the following types of file systems:

	fossil			the new Plan9 fileserver
	fossil+venti	fossil + a archival dump server

File system (fossil, fossil+venti)[fossil]:

--------------------------------------

Preparing menu...
The following tasks are done:
	configfs	- choose the type of file system to install

The following unfinished tasks are ready to be done:
	partdisk	- edit partition tables (e.g., to create a plan 9 partition)
	stop	- save the current installation state, to be resumed later

Task to do [partdisk]:

--------------------------------------
The following disk devices were found.

sd00 - Xen block device

sd01 - Xen block device

Disk to partition (sd00, sd01)[no default]: sd00
The disk you selected HAS NO master boot record on its first sector.
(Perhaps it is a completely blank disk.)
You need a master boot record to use the disk.
Should we install a default master boot record?

Install mbr (y, n)[no default]: y
mbr: reading boot sector: './disk' file does not exist

This is disk/fdisk; use it to create a Plan 9 partition.
If there is enough room, a Plan 9 partition will be
suggested; you can probably just type 'w' and then 'q'.

/bin/disk/fdisk: diskread 68 at 0.446: './disk' file does not exist

--------------------------------------

Preparing menu...
The following tasks are done:
	configfs	- choose the type of file system to install

The following unfinished tasks are ready to be done:
	partdisk	- edit partition tables (e.g., to create a plan 9 partition)
	stop	- save the current installation state, to be resumed later

Task to do [partdisk]: mercury# ls

Note the lines:
mbr: reading boot sector: './disk' file does not exist
and
/bin/disk/fdisk: diskread 68 at 0.446: './disk' file does not exist

I have made sure that DMA is off, and that the disk is writeable in the Xen config file.

This was tested with "plan9.iso" from http://plan9.bell-labs.com/plan9/download.html, as well as 9atom.

Here are some useful bits of information:

If I run "disk/fdisk -a /dev/sd00/data" in rc, I get the same response:
/bin/disk/fdisk: diskread 68 at 0.446: './disk' file does not exist

% cat > /dev/sd00/data
hello, world
cat: write error copying <stdin>: './cat' file does not exist
%

When I specify the entire path to /bin/disk/fdisk, the "'./disk' file does not exist" part doesn't happen.
/bin/disk/fdisk: diskread 68 at 0.446:

echo asdfasdfsdf > /dev/sd00/data && cat /dev/sd00/data
returns nothing, ie, the disk doesn't seem to have been written to.

% cat /dev/sd00/ctl
inquiry Xen block device
geometry 2097152 512
part data 0 2097152

% ls -l /dev/sd00
--rw-r----- S 0 glenda glenda          0 Feb 11  2010 /dev/sd00/ctl
--rw-r----- S 0 glenda glenda 1073741824 Feb 11  2010 /dev/sd00/data
-lrw------- S 0 glenda glenda          0 Feb 11  2010 /dev/sd00/raw

Thank you very much to 'f2f' and 'lmnopqr' in #plan9 on freenode for their help in trying to figure this out.

Thanks,
Alan C. Fisher

Re: [9fans] Weird plan9 Xen DonU problems

[Richard Miller]

> When I specify the entire path to /bin/disk/fdisk, the "'./disk' file does not exist" part doesn't happen.
> /bin/disk/fdisk: diskread 68 at 0.446:

Yes, this shows that %r in print(2) can be misleading if errstr
hasn't been cleared from a previous error.  The "file does not exist"
message is not relevant to your disk problem.

You've included lots of useful information but three more things
might help:

- what release of xen?
- what's in the xen config file?
- what does 'ls -l' say about the virtual disk file on the host OS?

Re: [9fans] Weird plan9 Xen DonU problems

[Alan C. Fisher]

> > When I specify the entire path to /bin/disk/fdisk, the "'./disk' file does not exist" part doesn't happen.
> > /bin/disk/fdisk: diskread 68 at 0.446:
>
> Yes, this shows that %r in print(2) can be misleading if errstr
> hasn't been cleared from a previous error.  The "file does not exist"
> message is not relevant to your disk problem.
>
> You've included lots of useful information but three more things
> might help:
>
> - what release of xen?
from "xm info" output:
version                : NetBSD 5.1 (XEN3PAE_DOM0) #0: Sun Apr 10 06:52:16 UTC 2011  acf@mercury.acfsys.net:/usr/src/sys/arch/i386/compile/XEN3PAE_DOM0
xen_caps               : xen-3.0-x86_32p hvm-3.0-x86_32 hvm-3.0-x86_32p
> - what's in the xen config file?
kernel = "/ort/xenimages/plan9/9xeninst-pae.gz"
memory = 96
name = "plan9"
vif = [ 'mac=aa:00:00:50:02:f5, bridge=0' ]
disk = [ 'file:/ort/xenimages/plan9/plan9.img,sda,w','file:/ort/xenimages/plan9.iso,sdb,r' ]
# This is the equivalent of plan9.ini:
extra="""
nobootprompt=local!/boot/bzroot
bootfile=sd01!cdboot!bootdisk.img
"""
> - what does 'ls -l' say about the virtual disk file on the host OS?
mercury# ls -l plan9.img
-rw-r--r--  1 root  wheel  1073741824 Sep 26 08:08 plan9.img
>
>

Thanks,
Alan C. Fisher

Re: [9fans] Weird plan9 Xen DonU problems

[Richard Miller]

I can't spot anything obvious.  I'm not aware of anyone trying
Plan 9 on xen on NetBSD before, so maybe there's something different
in that environment.

> -rw-r--r--  1 root  wheel  1073741824 Sep 26 08:08 plan9.img

You could try 'chmod 666 plan9.img', just in case it's a permission thing.

Re: [9fans] Weird plan9 Xen DonU problems

[Richard Miller]

I've put new 9xeninst binaries on sources which should replace the
spurious "file does not exist" message with a more accurate (but still
not very helpful) "i/o error".  I'm sorry I can't provide a better
diagnostic, but the xen virtual block device just returns BLKIF_RSP_OKAY
or BLKIF_RSP_ERROR.

I haven't been able to test it myself because I don't have a functioning
xen system at present.

Most of the interesting error diagnostics from the xen hypervisor itself
come out only on the serial console.  If you can hook up another machine
to display your xen system's serial output, you might get more info
about why the virtual disk i/o is failing.