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System Administration Guide: Virtualization Using the Solaris Operating System

Chapter 41 Troubleshooting Miscellaneous Sun xVM Problems

This chapter contains troubleshooting information for Sun xVM.

Dom0 Configuration Requirements

At this time, you should note the following issues when configuring dom0:

ZFS ARC limitation needed

ZFS must be prevented from taking too much memory from dom0. Limit the ARC by adding the following line to /etc/system:


set zfs:zfs_arc_max = 0x10000000

Reboot the system.

Limit dom0 memory

Limit dom0 to a specific amount of memory by using the Xen dom0_memoption. For example, if you have 4Gb of memory, give dom0 1Gb in /rpool/boot/grub/menu.lst:


...
kernel$ /boot/$ISADIR/xen.gz dom0_mem=1024M
...

If Text-Only Boot Was not Selected in OpenSolaris 2008.11 Installation

When installing OpenSolaris 2008.11, the "text-only" boot option from the GRUB menu should be selected. This is the second entry. However, the following workaround can be used if the text-only boot option is not selected.

  1. When the GNU GRand Unified Bootloader (GRUB) boot menu appears on the console, type e for edit before the boot selection times out and starts booting the default entry.

  2. The edit menu screen that pops up will have several lines on it. Use the down arrow key to scroll down to the line foreground, and type d for delete.

  3. Repeat the Step 2 process for the line background. Use the down arrow key to scroll down to the line that says background, and type d for delete.

  4. Using the arrow keys, scroll to the kernel line that contains the boot arguments, and type e for edit. Then, delete the entry for console=graphics.

  5. Press Return to exit line edit and save the changes, and then type b to continue the boot.

Verifying System Elements

ProcedureHow to Verify Devices in /dev/xen

  1. Change directories to /dev/xen and list the contents:


    # cd /dev/xen
# ls
balloon  domcaps  evtchn  privcmd  xenbus

ProcedureHow to Verify That the xvm Hypervisor Services Are Started

  1. Become superuser, or assume the appropriate role.

  2. Verify that the xvm services are running.


    # svcs -a | grep xvm

    If the system displays the following, the services are not running:


    disabled         Dec_07   svc:/system/xvm/store:default
disabled         Dec_07   svc:/system/xvm/xend:default
disabled         Dec_07   svc:/system/xvm/console:default

disabled         Dec_07   svc:/system/xvm/domains:default

  3. If the services are not running, verify that you booted an i86xpv kernel.


    # uname -i
i86xpv

    Reboot if necessary.

  4. If the correct kernel is running, enable the services.


    # svcadm enable xvm/store
# svcadm enable xvm/xend
# svcadm enable xvm/console
# svcadm enable xvm/domains

    You are now ready to create guest domains (domUs).

Tracing the Interaction Between dom0 and the Hypervisor

Due to the isolation of the hypervisor from dom0, there is currently no way to apply DTrace directly to the hypervisor. There is an xpv DTrace provider that allows you to trace the interaction between dom0 and the hypervisor.

To list the available DTrace probes, use the following command line:


# dtrace -l -i 'xpv:::'

To enable all probes, use the following command line


# dtrace -n 'xpv::: {}'

Guest Issues

Known OpenSolaris 2009.06 Guest Issues

Known Issues With Running Solaris 10 Guests on Other Operating Systems

For More Information

For additional documentation and more information about the hypervisor feature, visit the OpenSolaris community. The FAQ at this site will be updated to contain the latest issues.

For the latest information on dom0, see the document dom0 configuration for admins . See the document New Network Options, Including Limiting Bandwidth and Setting a VLAN ID, for Virtual Network Interfaces Attached to a Guest at this site to learn about new conventions for network options in virt-install.

xVM 3.3 documentation can be found on the OpenSolaris Community: Xen site.