Virtual SME Server

	Note:
	WIP. Place holder page for all things related to using SME Server as a virtualized server. Please add any info you feel is useful and someone from the doc team will format it nicely, so please go ahead!

	Skill level: Developer
	Thorough understanding of SME Server, configuration and virualization is required. Do not deploy in a production environment unless you are very confident you have the skills to manage and troubleshoot and find root causes of possible issues.

SME Server as a virtualized Guest server

Considerations

• Storage: Local, NAS, iSCSI, LVM, Raid
• Network: LAN/WAN, VLAN, VPN, Bandwith,
• Out of band access (VNC, SPICE)

'Hardware' configuration of a Virtual SME Sever

CPU

• Host CPU or emulate
• Sockets and cores

Memory options

• To balloon or to not to balloon

Disk options

• Virtio driver or legacy driver?
• Disk types pros and cons
• Disk I/O options

Network options

• Virtio driver or legacy driver?
• Bridge, NAT or Route?
• Bandwidth options

Installation options of a Virtual SME Server

Kernel options

• LVM (option nolvm)
• Raid (option raid=none)

SME Server configuration settings

NTPD

Timing related options are important within Virtual Guests and to the amount of 'pressure' it puts on the host and level/increasing CPU usage of the host and guest. By default SME Server uses the NTP deamon for 'timing' related matters, but by default is focussed on the above mentioned 1000HZ, hence the kernel option 'divider=10', thus reducing the timing cycles/context switching requests on the host. See the above VMWare document mentioned (Way at the bottom).

On a Virtual SME guest server the ntpd SupportLargeDrift DB variable can be enabled as follows:

config setprop ntpd SupportLargeDrift enabled

and

service ntpd restart

to activate the new configuration. This will adjust /etc/ntp.conf to 'better' settings for a virtual guest. By setting the above value to 'disabled', the NTP service and configuration will revert back to SME Server defaults.

Clock/frequency

As per suggestions in this article from VmWare and this one from Oracle on virtual Linux Guests, adjusting the guest Frequency will improve the guests speed.

You can check if your guest server can benefit from these boot options:

[root@sme8 ~]# grep CONFIG_HZ /boot/config-`uname -r`
# CONFIG_HZ_100 is not set
# CONFIG_HZ_250 is not set
CONFIG_HZ_1000=y
CONFIG_HZ=1000

If you see the above result, these boot options are useful.

For example, if your kernel boot line is:

kernel /vmlinuz-2.6.18-348.6.1.el5 ro root=/dev/main/root 

change it to:

kernel /vmlinuz-2.6.18-348.6.1.el5 ro root=/dev/main/root divider=10 clocksource=acpi_pm

	Note:
	We need to come up with a template fragment for grub.conf to make kernel options survive events.

SME Server as a Host server

• Phpvirtualbox
• Proxmox
• Xen
• QEMU/KVM
• VMWare