Installing Linux Integration Services v2.1 Hyper-V R2 On CentOS 5

When installed on a virtual machine that is running a supported Linux operating system, Linux Integration Services for Hyper-V provides the following functionality:


  • Driver support for synthetic devices: Linux Integration Services supports the synthetic network controller and the synthetic storage controller that were developed specifically for Hyper-V.

  • Fastpath Boot Support for Hyper-V: Boot devices now take advantage of the block Virtualization Service Client (VSC) to provide enhanced performance.

  • Timesync: The clock inside the virtual machine will remain synchronized with the clock on the host.

  • Integrated Shutdown: Virtual machines running Linux can be shut down from either Hyper-V Manager or System Center Virtual Machine Manager, using the “Shut Down” command.

  • Symmetric Multi-Processing (SMP) Support: Supported Linux distributions can use up to 4 virtual processors (VP) per virtual machine.


Hyper-v won’t start if you booted from Secondary disk on soft RAID1

You’re running a Hyper-V on a Server with 2 disks and using Windows Software RAID-1. Your primary disk fails and your windows crashes, but on the reboot you have an option to boot from a secondary “plex” disk. If you choose the secondary disk as it’s your only option to boot now, the boot configuration setting (kernel) of windows is not identical with primary disk. Hyper-V will not start because the hypervisor was not enabled in the boot configuration file. What you need to do is run this command:

bcdedit /set hypervisorlaunchtype auto


This will edit the boot config file and enable the hypervisor. You have to restart your server and don’t forget to choose the Secondary disk to boot from again.

How to Flush DNS on Mac and Windows

To flush or reset DNS on a Mac OS X type the following into terminal and run:

dscacheutil -flushcache


If you have older Mac OS X, this might work for you:

lookupd -flushcache


To flush DNS on any Windows version, click start > Run and type in command:

ipconfig /flushdns


Hope this fixes your DNS issues.

If you have any questions, please ask in comments.

Static IP vs Dedicated IP

There has been a lot of confusion between static and dedicated IP addresses. There are a lot of customers open a support ticket with request to get a static IP address. Today I would like to discuss this issue.


There are two types of IP addresses Dynamic and Static. Dynamic is the IP address that everyone receives automatically via DHCP server on home routers, wifi hot spots, etc. Basically anywhere you connect wirelessly or via cable and get internet connection automatically you get a dynamic IP address. Dynamic IP address can change when you connect next time. Servers cannot work with random IP addresses changes so we configure Static IP address on each server. So ALL servers have static IP addresses at all times. Static IPs cannot change randomly and assigned on a network card of each server. There can be more than one static IP address assigned to same server.


Shared Web Servers usually have a few IP addresses. By default all domains are assigned to just one IP address and all clients share this one IP address which makes this IP address a Shared IP. Technically it is possible to assign many domains to same IP address via binding in Internet Information Services (IIS7) and host headers in IIS6. Once a client wants to assign a SSL Certificate to his/her domain, shared binding/host headers are not possible anymore, so there is a requirement for a Dedicated IP. Once a dedicated IP is assigned to client’s domain, he/she is able to assign a SSL Certificate. The IP is now Dedicated to the client’s domain. The domain is no longer on a Shared IP address. Both Shared and Dedicated IP addresses are Static.


So it is incorrect to request a Static IP address from a web hosting company because all IP addresses are always static on all servers. Clients need to request a Dedicated IP address.