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NetWare Virtualized on Xen Tips

Novell Cool Solutions: Feature
By Glen Davis

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Posted: 5 Oct 2007

  1. Mount your NetWare Virtualized dos partition in the Linux host (Dom0)

    This can be really handy if you need to grab a logger.txt, or copy a file to or from the dos partition when troubleshooting server problems.
    Usage – lomount -t msdos -diskimage /path/to/nw/disk0 -partition 1 /mnt
    Example – lomount -t msdos -diskimage /etc/xen/images/oes2l/disk0 1 /mnt

  2. Don't leave the virt-manager gui running too long.

    Virt-manager gui has a memory leak (python consumes more memory over time), which should be fixed in an upcoming xen maintenance release. Shutdown virt-manager after viewing statistics or better yet, use the command line "xm top" and run gui-less to save system resources.

  3. Vncviewer access

    By default NetWare virtualized will use the virt-manager gui to display the virtual machine on the local Dom0 host. There is however an alternative method. You can use "vncviewer ::590x" to display the gui in a vnc window. Sometimes there is an occasion where a certain command won't work in the virt-manager gui, and the vncviewer can be used as an option. Example "vncviewer ::5902"

  4. Debugger Access

    When using the virt-manager gui, it does not recognize "shift-shift-alt-esc" to get into the NetWare debugger. Instead type "386debug", or alternatively use the vncviewer to access the gui (from #3), after disabling those keys from the Dom0 host shortcuts.

  5. Xenblk barriers

    Xenblk barriers is an important set parameter in NetWare virtualized. By default it is set at 16, and allows for data integrity in the event of a system crash, when using file backed disks or physical IDE or SATA drives. It can however be set to 0, which will give a nice performance gain, but with the drawback of the increased risk of corruption, should the power be shutoff, Dom0 crashes, or other types of uneventful failures. For example, "set XenBlk Barriers=0".

  6. Automated NetWare Virtualized installs

    Check out the new response file generator, that runs on linux, to create response files and automate your NetWare Virtualized installs. By default your Dom0 linux host will be installed with just SLES10-SP1. Add the OES2 product as an install source, then install the yast2-novell-responsefile package. Then look for the response file generator in YaST.

  7. Enabling Dom0 (host) to use more than 8 file disks

    When using file disks (IE. /var/opt/novell/xen//disk0 rather than /dev/sdb), the Dom0 will only allow eight of these file disks by default. Use the "losetup -a" command to see how many are in use. To enable for up to 64 , on Dom0 change /etc/modprobe.conf.local by inserting: options loop max_loop=64. then reboot the server with the change to make it effective.

  8. Enabling more than one network card for use in a Xen VM.

    In xen, each network card on Dom0 (host), needs to be tied to a xen bridge in order for it to be of use to a Virtual Machine. Unfortunately the bridging cannot be setup in the virt-manager gui at this time, so some manual steps are required. Bind each NIC on the Dom0 (host) to it's own ipaddress. Then setup a my-network-script as described at

  9. Set Dom0 to a certain amount of memory.

    It is a good idea to set Dom0 to use a certain amount of memory on every boot. Every so often some bug creeps up that seems to only be reproduced if memory is not set hard on Dom0. To set this, do xm mem-set 0 . For example xm mem-set 0 1024. A good amount to set is 20% of your total memory.

  10. NetWare Virtualized Coredump utility

    It is a planned that a utility that runs on the Dom0 host would be available soon to take coredumps of NetWare Virtualized, and be available though the support website. It will allow coredumps to be sent to Dom0, or to any server on the network running imghost.nlm or imghost.exe.

  11. Turn off powersaved

    It is best to turn off powersaved in Dom0, when running Virtual Machines, to avoid unwanted system hangs. To do this "chkconfig powersaved off", this will keep powersaved from running on subsequent reboots.

  12. Get familiar with xm commands.

    Type 'xm' to see a list of commands. There will be times you will need to administer your VMs through command line, so it is a good idea to get familiar with the xm commands. The 'xm dmesg' command is another good command to run on Dom0 to see any errors that may have occurred when troubleshooting a Virtual Machine problem.

  13. Restart your Dom0 Gui if the Gui has a problem.

    There is a current random bug, that occasionally makes the mouse pointer in the gui unresponsive. To fix the problem without rebooting. Toggle over to the command line "ctrl-alt-f2", login with root, then type "rcxdm restart". The gui login should appear. Login again, and all your vms should still be running.

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