Installation guide
Known Issues
31
• When running multiple guest domains, guest networking may temporarily stop working, resulting in
the following error being reported in the dom0 logs:
Memory squeeze in netback driver
To work around this, raise the amount of memory available to the dom0 with the dom0_mem
hypervisor command line option.
6.3.2. x86 Architectures
• Migrating paravirtualized guests through xm migrate [domain] [dom0 IP address] does
not work.
• When installing Red Hat Enterprise Linux 5 on a fully virtualized SMP guest, the installation may
freeze. This can occur when the host (dom0) is running Red Hat Enterprise Linux 5.2.
To prevent this, set the guest to use a single processor using the install. You can do this by using
the --vcpus=1 option in virt-install. Once the installation is completed, you can set the guest
to SMP by modifying the allocated vcpus in virt-manager.
6.3.3. x86_64 Architectures
• Migrating paravirtualized guests through xm migrate [domain] [dom0 IP address] does
not work.
• Installing the Virtualization feature may cause a time went backwards warning on HP systems
with model numbers xw9300 and xw9400.
To work around this issue for xw9400 machines, configure the BIOS settings to enable the HPET
timer. Note that this option is not available on xw9300 machines.
• Installing Red Hat Enterprise Linux 3.9 on a fully virtualized guest may be extremely slow. In
addition, booting up the guest after installation may result in hda: lost interrupt errors.
To avoid this bootup error, configure the guest to use the SMP kernel.
• Upgrading a host (dom0) system to Red Hat Enterprise Linux 5.2 may render existing Red Hat
Enterprise Linux 4.5 SMP paravirtualized guests unbootable. This is more likely to occur when the
host system has more than 4GB of RAM.
To work around this, boot each Red Hat Enterprise Linux 4.5 guest in single CPU mode and
upgrade its kernel to the latest version (for Red Hat Enterprise Linux 4.5.z).
6.3.4. ia64 Architecture
• Migrating paravirtualized guests through xm migrate [domain] [dom0 IP address] does
not work.
• On some Itanium systems configured for console output to VGA, the dom0 virtualized kernel may
fail to boot. This is because the virtualized kernel failed to properly detect the default console device
from the Extensible Firmware Interface (EFI) settings.