Hyper-V SCSI vs IDE Boot

Looking at the number of searches relating to this issue, it appears to be the biggest concern about Hyper-V so far.

While it is not acceptable that a Virtual Machine must boot from an IDE drive interface when the underlying storage is SCSI, it is possible that the IDE performance in Hyper-V could be better than pre-existing virtual SCSI storages (Virtual Server, for example). The virtualization team on Microsoft explains it better, but the new synthetic drivers on Hyper-V utilizes a much better way of providing virtualization, resulting in better performance. It is possible that the IDE driver in Hyper-V can perform better than SCSI driver in Virtual Server 2005.

We have yet to run a performance comparison between Hyper-V IDE and Virtual Server 2005 SCSI. However, once the integration services (synthetic drivers) installed on a Windows 2003 guest machine, it appears pretty fast.

Also, a SCSI hard drive can be added to a Virtual Machine and used as the data storage. We often seperate boot and data drives on servers anyways. Having a seperate data drive makes it easy to backup virtual machine data.

These of course, are just work arounds until Microsoft figures a way to boot Hyper-V machines from SCSI.

They must be working hard on it. 

Hopefully soon we will be able to run some performance comparison between Hyper-V and Virtual Server guest machines.

Networking issue with Hyper-V External Virtual Network

Pretty much like Virtual Server 2005, Hyper-V has options to create virtual network cards for guest machines that directly maps with a physical network adapter on the host machine. There is  an important issue that may surprise you, however, especially if you are working on a remote server.

When you create a virtual network and map it to a physical Network Adapter (External Virtual Network), Hyper-V automatically removes all protocols from the physical Network Adapter on the host machine and enables Virtual Network Switch Protocol. This means TCP/IP protocol is also removed! The host server will appear disconnected/offline from the outsite world. If you were working over remote desktop, you will be kicked out, and won't be able to connect anymore.

All you have to do is re-enable TCP/IP on the physical Network Adapter in order to bring the server back online. Which of course you can't do unless you are logging in locally.

It is not a big deal if you have a second network card that is also connected to the Internet. In fact thats how I was saved, twice.

Why does Hyper-V remove all protocols from the physical network adapter except virtual networking? Is there some stability issues? Security issues? poor performance? I have yet to check the documentation on this.

But if you are reading this before it is too late, at least you can be prepared.

Hyper-V Limitations

Since my initial review on Hyper-V, many visitors ended up on this blog from google and other search engines searching for Hyper-V related information. While some of them were looking for a review of Hyper-V, most were actually looking for solutions to problems they are facing with Hyper-V. Now that several weeks have passedt and I have accumulated a good number of popular search phrases about Hyper-V leading to this Website, I can list what appears to be the most common problems or limitations of Hyper-V based on the frequency or repetition of these search phrases.

1. Remote Access of Guest Machine Console
   Not being able to connect to to a Hyper-V guest console with VMRC like client seems to be the biggest problem. With the release of Hyper-V management control for Windows Vista SP1, this problem is reduced a little bit. But not too many people use Vista yet, none of the workstations that are in my control (about 15 of them) has Vista installed. Also, when connecting to a remote server via MMC, firewall configuration may be an issue.
2. Guest Machine Console over Remote Desktop
   Although Microsoft is very straight froward in saying Hyper-V guest machine console is not supported over RDC, many of us seem to have no choice! The biggest problem seems to be mouse capture. Hyper-V release candidate don't even try to capture mouse when running within a Remote Desktop. Installing integration components does fix this issue, but not with Linux guest installations.
3. Boot from SCSI
   I mentioned in my original review that Hyper-V final release better be able to boot from SCSI. As of RC0, it does not, and people are searching to see if it is possible. No one would want a server to run on IDE, specially when the underlying physical storage is SCSI. I don't like it, no matter how efficient the synthetic IDE driver is, there has to be some overhead in traslating IDE to underlying SCSI physical interface. So let me say this again: Hyper-V final release better be able to boot from SCSI!
4. Various flavors of Linux distribution installation as guest OS
   Search terms seem to favor Ubuntu, SUSE and Fedora. But this is probably because I have made posts relating to these distributions. I think  all popular Linux distributions would be in demand.
5. Slow connections over network
   I personally did not experience slow network performance, but people seem to be searching about it.
6. Network access for Linux guest installations
   There are two solutions to this: install Linux integration components, or use a Legacy Network Adapter. You can add Legacy Network Card from Hyper-V machine's Settings - Add Hardware option.

Of course, quite a few people did search for a review on Hyper-V, and some were looking for comparisons between Hyper-V and Virtual Server 2005.

Install Ubuntu 7.10 on Hyper-V

In my previous post about installing Ubuntu on Hyper-V, I mentioned that while Ubuntu 6.06 installs on Hyper-V, Ubuntu 7.10 does not. This problem can be solved by applying a patch on Ubuntu 7.10 installation ISO. You can download this patch from here. It is a small executable that looks for Ubuntu 7.10 installation ISO files in the current directory, and if found, applies the patch to them. Simple enough.

Once the patch applied, I was able to Install Ubuntu 7.10 on Hyper-V (Server edition with LAMP) without any problems. Better yet, the Hyper-V console worked fine during and after installation without any graphics related issue.

Of course, the server edition of Ubuntu does not install a GUI and it boots into console mode, but even the console of version 6.06 did not work properly on Hyper-V. 

Now that Ubuntu is up and running, I have to figure out how to install Webmin on it. Also, does it come with IP Table enabled by default?

Installing Ubuntu on Hyper-V

Okay, I was able to install Ubuntu 6.06.2 on a Hyper-V virtual machine. Ubuntu 7.10 simply remains with a blank screen at startup. So does Open SUSE 10.2, but this 6.06.2 Ubuntu server installed with a little bit of tweaking.

Before beginning installation, you have to remove the default Network card that is added during the initial setup of the virtual machine, and add a 'Legacy Network Card'. That is, if you want network connectivity. 

There are many variations of Ubuntu, even the same version has various distributions. The version I downloaded had a VGA (F4) option on the installation menu which can be used to set the installation to VGA 640x480 mode. This is the biggest problem during installation; setting the display to 640x480.

Hard disk partitioning seemed to fail on the first run, but on second try installation went smooth. Ubuntu on Virtual Server had an issue of not being able to detect the Virtual CD/DVD Drive, which is not there on Hyper-V, at least with this version of Ubuntu.

After installation, though, Ubuntu boots with incompatible display settings and characters are pushed down the console and I could not see the command prompt. Rebooting in 'recovey mode' got me on the console with root access. Now all I have to do is set the display to 640x480 and everything should be fine.

From various sources and blogs on the net it appears that I need to modify /etc/X11/xorg.conf file to change the display settings of Ubuntu, and for some reason, I can't find it!

Is it because it is the server version of Ubuntu?

Lets hope that with a little bit more research, I will be able to figure this out soon.

If you do not have the integration services installed, the Release Candidate of Hyper-V won't capture mouse on Hyper-V connections over a remote desktop, since it does not work anyways. The only server I have with Hyper-V at this moment is in a Datacenter and I can only access it with a remote desktop. This leaves me with only the keyboard to work with. Installing and subsequently working with Fedora with only keyboard was quite an adventure! 

Installing Ubuntu was much faster than installing Fedora 8!