Citrix Systems 6.2.0 manual Installing a VM from Reseller Option Kit BIOS-locked Media

The following table lists wallclock settings for Linux VMs:

Guest OS	Dependent wallclock	Independent wallclock
CentOS 4.x	Default	Optional
CentOS 5.x (32-/64-bit)	Default	Optional
CentOS 6.x (32-/64-bit)	Not supported	Default
Red Hat Enterprise Linux 4.x (32-bit)	Default	Optional
Red Hat Enterprise Linux 5.x (32-/64-bit)	Default	Optional
Red Hat Enterprise Linux 6.x (32-/64-bit)	Not supported	Default
OEL 5.x (32-/64-bit)	Default	Optional
OEL 6.x (32-/64-bit)	Not supported	Default
SLES 10.x (32-/64-bit)	Default	Optional
SLES 11.x (32-/64-bit)	Default	Optional
Debian 6.0 (32-/64-bit)	Not supported	Default
Ubuntu 10.04 (32-/64-bit)	Not supported	Default
Ubuntu 12.04 (32-/64-bit)	Not supported	Default

Important:

•For Linux guests that support dependent wallclock, Citrix recommends enabling independent wallclock setting and using NTP inside the VM.

•For Linux guests that use an independent wallclock, Citrix highly recommends running a reliable NTP service on the Linux VMs and the XenServer host.

Refer to the following section to set the independent wallclock time.

To set individual Linux VMs to maintain independent times

1.From a root prompt on the VM, run the command: echo 1 > /proc/sys/xen/independent_wallclock

2.This can be persisted across reboots by changing the /etc/sysctl.conf configuration file and adding:

# Set independent wall clock time xen.independent_wallclock=1

3.As a third alternative, independent_wallclock=1 may also be passed as a boot parameter to the VM.

Note:

When installing a new Linux VM, make sure that you change the time-zone from the default UTC to your local value (see Section B.1, “Release Notes” for specific distribution instructions).

9.8. Installing a VM from Reseller Option Kit (BIOS-locked) Media

A XenServer VM can be:

•BIOS-generic: the VM has generic XenServer BIOS strings;

•BIOS-customized: the VM has a copy of the BIOS strings of a particular server in the pool;

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