Getting stubdom to work on Xen 3.3 port via to CentOS 5.2

September 27, 2008

Created in /etc/xen files:-

[root@ServerCentOS52 xen]# cat WinXPhvm-stubdom
kernel = “/usr/lib/xen/boot/hvmloader”
memory = 512
name = “WinXPhvm”
vif = [ ‘type=ioemu, bridge=eth0’ ]
device_model = ‘/usr/lib/xen/bin/stubdom-dm’

[root@ServerCentOS52 xen]# cat WinXPhvm-dm
kernel = “/usr/lib/xen/boot/ioemu-stubdom.gz”
vif = [ ‘ ‘, ‘bridge=eth0’]
vfb = [ ‘type=sdl’ ]
# vfb = [ ‘type=vnc’ ]
disk = [‘file:/etc/xen/isos/winxp.iso,hdc:cdrom,r’,’file:/etc/xen/images/disk.img,hda,w’,’file:/tmp/test,hdb,r’]

Per Xen 3.3 Stubdom Release Notes run:-
# mkdir -p /exports/usr/share/xen/qemu
# ln -s /usr/share/xen/qemu/keymaps /exports/usr/share/xen/qemu
#  mkdir -p /exports/var/lib
#  ln -s /var/lib/xen /exports/var/lib
# /usr/sbin/fs-backend &

Switch from console to another terminal session :-

# xm create WinXPhvm-stubdom

In original hvm profile both vnc and sdl are disabled.
Selection is made *-dm Domain’s profile. Both option “sdl” or “vnc” work with the same performance.
However, vnc connection is preferable from my standpoint. Mouse just gets lost with SDL in final phase.
Second option requires connection to Vncserver at Dom0 :-
# vncviewer localhost:0
after “xm create WinXPhvm-stubdom”.
In both cases install goes hardly alive with long outages , looks like it gets stuck from time to time.
I’ve also added to runtime profile:-
to improve mouse behavior in VNC session. It works as usual. I’ve also set up mem_dom0 to 4GB on 8GB box, but
WinXPhvm-dm allocated only 32 MB, no matter of mem_dom0’s size. I would guess bad Xen Hypervisor tuning on Dom0 due to limited experience from my side. Otherwise, performance is significantly worse then in usual HVM DomU. Same install for CentOS 5.2(1) just hangs on the third page “Keyboard Layout Selection”,
Solaris Nevada Build 98 generates following error at startup:-
Configuring /dev
ata_command: BSY too long!DRDY 0x1 CMD 0xe0 F 0x0 N 0x0 S 0x0 H 0x0 CL 0x0 CH 0x0
and obviously exists after configuration phase with message :-
No hard disk found

I was also able successfully and fast install in stub domains F8,F9,openSUSE 11,Ubuntu 8.04.1 Desktop
and Solaris 10 (05/08). For CentOS 5.2 (1) installer hangs at third page “Keyboard layout selection” and never comes back to live. Monitoring “xm list” i was waiting for a while, it looked like CPU resource had been taken by stub domain.
All mentioned Linux distros are 64-bit.

What’s amazing it’s installation and runtime performance Solaris 10 (05/08) (32-bit) in stubdom vs Windows XP.
I would expect some old fashioned IDE emulation providing by /usr/lib/xen/bin/stubdom-dm , not understandable
by Solaris Nevada 98. Boot up / Shutdown speed of S10 in stubdom seems to be very fast ( just close to HVM DomU)

[root@ServerCentOS52 xen]# cat s10hvm-stubdom
kernel = “/usr/lib/xen/boot/hvmloader”
memory = 1024
name = “s10hvm”
vif = [ ‘type=ioemu, bridge=eth0’ ]
device_model = ‘/usr/lib/xen/bin/stubdom-dm’

[root@ServerCentOS52 xen]# cat s10hvm-dm
kernel = “/usr/lib/xen/boot/ioemu-stubdom.gz”
vif = [ ‘ ‘, ‘bridge=eth0’]
vfb = [ ‘type=vnc’ ]
disk = [‘file:/etc/xen/isos/s10.iso,hdc:cdrom,r’,’phy:/dev/sdb12,hda,w’,’file:/tmp/test,hdb,r’]

OpenSUSE 11 snapshots :-