Aidan Finn: Hyper-V

Introducing SCVMM 2008 Performance & Resource Optimization (PRO)

Wed, 13 Aug 2008 09:26:09 GMT

Why do I prefer Hyper-V, a version 1.0 hypervisor, over the more mature VMware ESX? It's quite simple; management. This is where the "religious" VMware nutters scream about Virtual Center and ESXi web consoles - hold on to your hats, girls, this ones gonna be a bone shaker!

I am a "laxy admin". I do not like to be poking and prodding in machines and consoles on a constant basis to do repetitive work. There's better things that I can be doing such as actual engineering projects or working on the business side of things. I also like to know when something has gone wrong, either before it happens or before the customer calls us up. The traditional solution seems to be to have lots of management consoles all over the place. Honestly, that doesn't work. Once server and application crawl takes over, there's too much fire fighting involved in working with lots of management solutions.

Here's why I like HP (Dell play nice too AFAIK) and Hyper-V. The fit in nicely with the concept of Optimised Infrastructure by being very manageable, more than their competition. The idea is that you design your network, servers and applications so that they are easy to manage. This means using integration and automation so there is less manual work to be done, the service is fault tolerant and reliable, you can focus on developing/enabling the business and the service that IT provides can be counted on. We also reduce our operating costs. Understanding these concepts and being able to use them is the difference between employing 15 IT staff and 77 IT staff (based on a real-world example).

So back on point ... what's all this got to do with Hyper-V? MS's System Center family of products are an integrated set of management tools to designed to build that automation and expertise into your network. Yes, in the past they were MS centric but partners did expand them to include 3rd party solutions, e.g. *NIX and Cisco. Now, MS is even doing this themselves. One of the core products they sell is OpsMgr 2007, the monitoring solution. Using an OpsMgr agent with management packs, I have expertise on different products that knows what to monitor, what is acceptable, what faults to watch for, best practices, etc. I can even extend this or tweak it with exceptions. This allows me to sit back and know that someone ... or something ... is watching my hardware, OS and applications.

Here's the fun bit. There's soon going to be a management pack for Hyper-V. That means we get in-depth expertise for monitoring the health and performance of the virtualisation platform using the same single pane of glass that I use to monitor everything else.

So those VMware marketing types who try to sell ESXi off as being equal to Hyper-V, answer me this? Where do I install an agent on a machine with no OS? I've heard that I can monitor the hardware using cards in the server; what good is that for monitoring the hypervisor? You answer me that the hypervisor has a web console. Fantastic! Do I really want to log into lots of little web consoles? Ah ... Virtual Center ... so now I need to use it and my console that manages everything else? Virtualisation is meant to be good for a lazy admin like me ... you know .. less work, put my feet up, more time for playing games, etc.

Microsoft's answer to Virtual Center is Virtual Machine Manager 2008 which is being launched on September 8th. VMM 2008 gives us management over the VM's on our Hyper-V servers or cluster. It includes the ability to audit physical machines to see if they're candidates for virtualisation (don't even have to pay for that agent license!) and a P2V conversion tool. VMM 2008 integrates with OpsMgr 2007 SP1 via PRO or Performance and Resource Optimization. You can read much more about that here. The idea is simple. OpsMgr monitors performance/health and understands the relationship between VM's and hosts. VMM 2008 manages VM creation and placement. PRO links the two to share that knowledge and act on it. What's really cool is that we're getting cradle-grave management of hosts and VM's. But not only at the hypervisor, but all the way through the "stack" from the hardware, the host virtualisation, the VM and the VM's OS and applications.

That means I have a single integrated management solution for my entire network. I'm a big believer in infrastructure optimisation. I've witnessed it working and making my life easier. I've also witnessed the opposite where there was no management despite there being lots of junkware being installed to "manage" points of the infrastructure. Automation, expertise and integration are the keys to success. For me, that's why I like HP servers/storage and Hyper-V because they can be easily managed using Microsoft System Center.

Windows 2008 User Group Event: Hyper-V and Virtual Machine Manager 2008

Thu, 07 Aug 2008 11:36:27 GMT

The Windows Server 2008 User Group (Ireland) will be running an event on Hyper-V and System Center VMM 2008. There will be 3 sessions:

Dave Northey (Microsoft): Hyper-V - we can get a little deeper on this topic now that the product has been released.
Aidan Finn (ME) (C Infinity): Lessons I've learned about Hyper-V - Aidan will share his experiences with the product and things you should be aware of when setting up a lab or production environment.
Mark Gibson (Microsoft): Virtual Machine Manager 2008 - System Center VMM2008 is due to be released in Q3 2008. It is Microsoft's answer to VMware's Virtual Center and will be an essential tool for managing production Hyper-V deployments.

Attending The Event

The session is free to attend for members of the Windows Server 2008 Users Group. Membership and joining the group are free. Once you are joined, we will send an invite out to you - assuming there are places still free.

Places are limited to 20 so book now while you can.

Patch For Hyper-V in Clustered Environments

Thu, 07 Aug 2008 10:27:19 GMT

I was told a little while ago to watch out for this patch from Microsoft. It improves how Hyper-V works in a clustered host environment. KB951308 can be downloaded once you accept a EULA. You should have a read because there is a long list of improvements.

Note that:

If you apply this update to a computer that is functioning as a Windows Server 2008 failover cluster, the failover cluster service must be restarted before the changes will take effect.
If you apply this update to a system that is running the Failover Cluster Management console (the Cluamin.msc file), any open versions of this management console be closed and reopened before the changes will take effect.

Make sure you test this update before you or your company decide to install this update.

Deploying Windows Server 2008 Hyper-V and Microsoft System Center Virtual Machine Manager: Best Practices

Wed, 06 Aug 2008 16:19:58 GMT

I've just watched this presentation by MS on Hyper-V and SCVMM 2008. If you're planning on deploying either or both of these technologies then this presentation is essential viewing.

Hyper-V Deployment Guide

Mon, 28 Jul 2008 08:19:37 GMT

Microsoft has released a deployment guide for Hyper-V. I'll be giving it a read later today to see what it's like, assuming that meetings don't eat up my day.

Hyper-V Clusters - There Are Only 26 Letters In the Alphabet

Thu, 24 Jul 2008 09:00:36 GMT

If you've looked at putting Hyper-V in a cluster you might have read Jose Barreto's blog post on clustering options, viewed Dave Northey's videos demonstrating it in action or considered trying to recreate what ESX with Virtual Center does. You'll soon see that to have failover or mobility on a per-VM basis with Hyper-V on Windows Server 2008, each VM must reside in it's on disk/LUN on your shared storage. Windows Server 2008 doesn't have the ability (yet) to do shared file systems like that in ESX's VMFS.

You'll now think ... I can have 16 nodes in a cluster and potentially dozens of VM's in my N+1 or N+2 architecture. Wait ... how many drive letters am I going to need? I've already consumed A, B, C and D ... does this mean a cluster can have only 22 VM's? This is probably something where some certain-product-fanatic gets to write some blog FUD without digging just a little deeper. It's amazing to see how prejudice is tainting the commentary and reviews that are out there right now :-)

You have the option to use "letterless" drives in Windows Server 2008. Instead of using a drive letter to identify the physical drive that each VM can reside on, you can use a GUID to identify the drives.

The only question now is, how do you use these drives? VirtuallyAware has done a post on the subject. The hardest part of the process is getting the GUID of the LUN that you're working with. Who really wants to type out something nasty like "fc247e42-0a5e-11dd-94db-001b785788b0"? PowerShell helps at there as the blog post indicates.

You'll now have a virtually unlimited set of drive identifiers that will allow your cluster to scale out to the limitations of your CPU, storage and RAM.

On a tangent, this is just another example of where PowerShell is a necessary skill, not only in PowerShell but in all new MS technologies. I've started learning it. It's different, that's for sure, but it's not optional any longer.

Hyper-V Snapshots Under The Hood

Thu, 24 Jul 2008 08:36:44 GMT

This article gives you a quick and easy to understand look under the hood so you can see how snapshots work in Hyper-V.

Credit: HyperVoria.

Beware Anti-Virus and Hyper-V

Mon, 21 Jul 2008 13:28:28 GMT

I released the July updates onto our network this past weekend. I'd also deployed our new AV the previous week. Let's just say that AV mixed with Hyper-V and followed by a reboot made for a nice mess.

I logged into the Hyper-V lab this morning to find half of my VM's were missing. They're sitting find (but idle) on the storage. It's just Hyper-V has "forgotten" that they ever existed.

I trawled through the Windows Event logs (Application and Service logs - Microsoft - Windows - Hyper-V-Config - Admin) and found a series of these:

Source: Hyper-V-Config

Event ID: 4096

Level: Error

The Virtual Machines configuration <big long GUID> at <path to VM> is no longer accessible: The requested operation cannot be performed on a file with a user-mapped section open. (0x800704C8)

Ok. A bit of googling found an entry on the TechNet forums that says you need to disable scanning for the VHD's and the XML files of your VM's. Ouch!

OK, so I did that and rebooted by lab server. Still no dice. Actually, Hyper-V doesn't even bother attempting to load these VM's now. OK, I'll do what I would in any other virtualisation product; I'll open them. Ick ... no open command. Import? Nope; because MS in their wisdom (!) decided that the import/export format should be different to that of a normal VM.

So I've got a plethora of VM's that are sitting on my disk in a saved state that I cannot load up. My only way forward is to re-add the virtual hard disks as new VM's. This is a pain:

I lose my saved states.
I have to reconfigure every single VM that is missing.
Each VM has to do the PNP dance with a "new" NIC and I have to reconfigure IPv4 addressing.
It's just lots of work I shouldn't have to do.

I've logged a bug report with MS. I'm open to any constructive suggestions.

How A Hyper-V VM Perceives Logical Processors (Cores)

Fri, 18 Jul 2008 12:05:53 GMT

The Virtual PC guy has done a very nice job in explaining how a VM is aware of the difference between a physical and a logical processor.

Hyper-V RAM Calculator

Fri, 18 Jul 2008 11:42:56 GMT

I've previously discussed how RAM is used by Hyper-V in terms of:

The parent partition
Hyper-V services
Drivers
Guest RAM allocation overhead.

I've put together an Excel spreadsheet that calculates how much RAM is consumed by a VM as you load it onto a host. Using it is easy:

Specify how much RAM is in the physical host machine.
Add each guest VM and enter how much RAM (in GB) you want to allocate to the guest.
The RAM utilised by the guest is calculated and the amount remaining on the host is presented.

The numbers you need to enter are highlighted in yellow.

The formula used assumes maximum RAM overhead, i.e. the worst case scenario of 32MB for the first GB and 8MB for each GB after that on a per VM basis. I'm also allowing 300MB in addition to the 2GB recommended as the reserve for the parent partition. Often, this can be considered a part of the 2GB. You can recalculate things by adding in another line item to specify driver requirements for the parent OS if you want.

Hyper-V Controllers: IDE or SCSI?

Thu, 17 Jul 2008 09:24:05 GMT

There's been plenty of blog posts out there saying that there is no support for SCSI in Hyper-V. That's not true. What is true is this. You can use SCSI controllers for disks but not for your boot disk. Your boot disk must be on an IDE controller.

Some facts:

IDE

Hyper-V uses en emulated IDE controller. This means there is a little bit of overhead in processing disk operations. That's not so bad for lightweight VM's. You can have two IDE controllers, each with 2 devices. One of these is your virtual DVD drive which you should probably disconnect when you don't need it.

SCSI

Hyper-V uses a SCSI controller that is not emulated. Instead it uses the virtual machine bus which is much faster and requires less CPU overhead.

Setting Up VM's

How do you set up your VM's? You have no choice about your boot disk. You must use a disk connected to the IDE controller. You can't move that to the SCSI controller because you cannot boot from a Hyper-V SCSI controller. Lightweight VM's can probably put everything on one virtual disk and run on the IDE controller.

However, best practice is to separate your data/workload from your operating system. Consider a virtual application server where the operating system is on C: and the workload is on D:. C: will be a virtual disk on the IDE controller. D: should be a virtual disk on a SCSI controller. This makes the most of the underlying Hyper-V architecture and optimises CPU utilisation on the host server.

I'd recommend that you read some of the blog entries on All Topics Performance. I found two (1 and 2) to be rather interesting.

Offline Virtual Machine Servicing Tool

Fri, 11 Jul 2008 08:21:36 GMT

.I've just read about the Microsoft Offline Virtual Machine Servicing Tool. The idea is that many organisations keep a certain number of VM's in an offline state. Maybe they are used once in a while. Maybe they are archived for regulatory reasons. However, there is a chance they need to be powered up once in a while. What is the risk that they power up and are not sufficiently secured by updates? Are you really going to manually power them up every month to deploy updates and human resources?

Microsoft has the Virtual Machine Service Tool accelerator to take care of this for you. It runs a servicing job (using PowerShell scripts) to power up the VM, deploy updates using either WSUS 3.0 or SCCM 2007 and then powers down the VM.

The product has recently been released by Microsoft. It's a free download and well worth checking out if you have a limited virtual lab or large production environment that utilises MS virtualisation.

I don't see any support for Hyper-V yet. Maybe that's coming - I've sent in a question to find out. There's a dependancy on VMM. VMM 2007 only supports Virtual Server 2005 R2 SP1 so I guess we'll have to wait and see on VMM 2008 (RTM Q4 2008).

Its requirements are:

Supported Operating Systems: Windows Server 2003 R2 (32-Bit x86); Windows Server 2003 R2 x64 editions; Windows Server 2003 Service Pack 2.
Other Requirements: .NET Framework 2.0, .NET Framework 3.0, IIS with ASP .NET installed, Windows Remote Managment, Windows PowerShelll 1.0, Configuration Manager 2007, WSUS3.0, Virtual Machine Manager 2007 (VMM), Virtual Server 2005 R2 SP1 or higher, Windows Server 2003 R2 SP1 or higher, Active Directory, SQL Server 2005 SP1 or higher, SQL Server 2005 Express Edition (VMM only).

System Center Management Suite Enterprise and VMM 2008 Release

Fri, 11 Jul 2008 08:09:39 GMT

I've just read about some licensing changes for the SMSE CAL. This CAL entitles you to license a physical device (and hence all the VM's on it) for the following System Center products:

Operations Manager
Configuration Manager
Data Protection Manager
Virtual Machine Manager

You're probably aware that VMM 2008 is in beta at the moment. The System Center team blog says that it will be released in Q4 2008. Along with this it will be included to replace VMM 2007 in the SMSE. VMM 2008 will also be available as a standalone product. It can make sense to use the SMSE because it works out around the price of the CAL's for two of these products. VMM and SCOM can work very closely together offering an almost consultancy/advisor like experience for MS virtualisation (Virtual Server and Hyper-V).

It is expected that the cost of the SMSE will increase by 10-15% at this time.

Credit: Bink.

Installing Hyper-V on Server Core

Thu, 10 Jul 2008 20:41:23 GMT

I finally got around to installing Hyper-V on Server 2008 Core at home. I'm building a lab to do some work on SCCM 2007 SP1 and R2 and I figured I rebuild my Vista desktop with Core so I could provision more RAM for my VM's.

My desktop is a 4GB RAM "home build" that I got on Komplett back in September 2006. Imagine trying to install ESX on that? LOL. One of the great perks of Hyper-V is that it will support anything that Windows Server 2008 can install on.

Here's what I did to get going:

Enabled CPU virtualisation assistance and DEP in the BIOS.
Installed Windows Server 2008 Enterprise x64 (Core Installation). This takes no time at all. It was using about 6GB of disk and around 500MB of RAM.
Changed the regional settings: I am in Ireland but my wireless keyboard is USA: control intl.cpl.
Determined the NIC ID (I have a few in it): netsh interface ipv4 show interfaces.
Set the IP address for NIC 2: netsh interface ipv4 set address name="2" source=static address=192.168.1.3 mask=255.255.255.0 gateway=192.168.1.1.
Set the DNS: netsh interface ipv4 add dnsserver name="2" address=192.168.1.2 index=1.
Renamed my server: netdom renamecomputer %computername% /NewName:HyperSvr1.
Rebooted for that to take effect: shutdown /r /t 0.
Joined it to my SBS domain: netdom join %computername% /domain:mydomain.local /userd:administrator /passwordd:*.
Rebooted for that to take effect: shutdown /r /t 0.
Copied CoreConfigurator onto the Core server and configured any users, groups, enabled RDP, firewall settings that I needed.
Downloaded and copied the Hyper-V update onto the server.
Installed the Hyper-V update: wusa.exe Windows6.0-KB950050-x64.msu.
Installed the Hyper-V role: start /w ocsetup.exe Microsoft-Hyper-V.
Rebooted when prompted.
Downloaded and installed Remote Management for Windows Vista. Using this I can manage my headless Core "server" from my laptop and do all my lab work in a more comfortable location.

Hyper-V Just Isn't For The Enterprise! Pfft!

Thu, 10 Jul 2008 10:41:15 GMT

It's not so long ago we used to hear the following from Novell Netware heads:

Windows isn't scalable.
Active Directory isn't good enough. You can't build an enterprise on it.

And guess what ... that sort of hot air usually came from people who hadn't even tried Windows or AD on normal production hardware or even at all. Over the last 5-6 years we've seen NDS disappear faster than Tyrannosaurus Rex and consultants making a fortune doing Netware-to-AD migrations. AD is reliably managing 10's and 100's of thousands of users and probably more.

Now I get great pleasure in reading from vested interests that Hyper-V isn't up to the job. "It can't be used in an enterprise". "It's only good for testing". That sounds very familiar, eh? And again, it's pure trash! I've been hammering Hyper-V over the last while since it was a release candidate. It performs beautifully. I can't complain about it. Easy to install, easy to set up VM's and reliable. I've not had one outage. VM's are lightening fast. I've been even using differencing disks and haven't had any issues (not that I recommend differencing disks for production). Don't just take my word for it either.

I've read a lot of critiques by the vested interests and they make me laugh. They are so obviously commenting from a standpoint where they haven't even tried the product in the last 6 months.

Before anyone goes nuts; ESX is an excellent product. There are certain reasons why I would choose it over Hyper-V and there are reasons why I would choose Hyper-V over ESX. And I'm sure Xen is probably excellent too, but to be honest, if I'm paying extra for virtualisation outside of the System Center management scope, I'll go for ESX.

If you are looking at Hyper-V as a potential solution then try it. That's the only true test. Remember that us bloggers are very often no better than you. Look for credentials. Look for evidence that they've tried what they are talking about. If the commentary is too one sided then watch out for the "Fair and Balanced" alarm bells ;-)

PowerShell Management and Hyper-V

Thu, 10 Jul 2008 10:19:48 GMT

I've fallen behind with PowerShell. There's a bazillion things to do and this is one of them but I've not been able to learn the language yet. There's a plan: one of the books I bought recently is a cookbook for PowerShell coding for SCOM and Windows.

Anyone who likes PowerShell will love Hyper-V and everything about it. It's very manageable from the scripting language. Taylor Brown has dedicated a lot of time giving Hyper-V coding examples. The Virtual PC Guy has noted that James O'Neill just posted a free to use PowerShell library for Hyper-V.

Hyper-V KVP Exchange aka Data Exchange

Thu, 10 Jul 2008 09:43:26 GMT

Taylor Brown has been running a series of posts on his blog about Hyper-V Data Exchange. It's one of the integration services available on each VM. The idea is that you can query a certain section of the registry (HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Virtual Machine\Guest\Parameters) on either the guest or the parent. You can also write to there as well.

That brought up a question in my mind. There are some environments where this would be very bad. Can you disable this? Sure you can! Open up the properties of the VM in question and clear the tick box for the Data Exchange integration service. Voila: it's disabled.

Hyper-V available via Windows Update

Thu, 10 Jul 2008 09:38:53 GMT

The Hyper-V team announced that Hyper-V was available via Windows Update (and WSUS) since Tuesday. It is available as a recommended update.

Top 5 things to know about Hyper-V

Tue, 01 Jul 2008 09:21:09 GMT

The Microsoft Windows Virtualisation team has posted a blog entry on the top 5 things you need to know about Hyper-V. It covers:

The Hyper-V architecture and how it performs much better than Virtual PC or Virtual Server. It's a hypervisor with a very slim architecture making it much faster.
Snapshots - Yes! Hyper-V has snapshots just like we lab rats have been using in VMware Workstation for years. It's quite fast too, even on a less than recommended disk specification.
Quick Migration - No, it is not VMotion and we likely won't see "live migration" for a few years in Hyper-V. Question you have to ask yourself is: do you really need it? Think about why you would willingly move a VM in ESX (not failover because both products are essentially the same here).
System Center Virtual Machine Manager 2008: Offers that layer of management that ESX admins associate with Virtual Center. However, it integrates with SCOM 2007 and can manage Virtual Server and ESX.
Hyper-V can run on Server Core. This minimises your resource requirements for the parent partition, reduces the attack surface and reduces the numbers of possible patches.

Deploying Windows Server 2008 with "slipstreamed" Hyper-V RTM. Part 1.

Sat, 28 Jun 2008 11:07:48 GMT

John Howard has started documenting how to "slipstream" Hyper-V into the install image for Windows Server 2008. That'll be pretty handy if you want to be able to rapidly deploy Hyper-V hosts, e.g. a rapidly growing farm of hosts.

Credit: John Howard.

Hyper-V Release Notes

Fri, 27 Jun 2008 17:36:54 GMT

If you are installing the RTM of Hyper-V then you really should read the release notes. There's information in there relevant to backup, security and operations.

Delegation of Administration in Hyper-V

Fri, 27 Jun 2008 17:27:11 GMT

If you're like me, you like to restrict as much as possible and delegate selected rights where possible. I've only just found out that this is possible with Hyper-V without using VMM 2008.

The Virtual PC's Guy describes the process in his blog. This will allow you to grant selected rights to VM's and Hyper-V to non-administrators on the Hyper-V server. To do this you edit an Authorisation Store using the Authorisation Manager.

Note that this is in the Hyper-V release notes:

"If the Hyper-V authorization store is located in Active Directory, then the removal of a user from a role does not take immediate effect. Either the server running Hyper-V (the computer that runs the Virtual Machine Management Service (VMMS)) or Active Directory needs to be rebooted to apply the changes. To avoid this issue, use an XML file as the store type. To fix this issue, reboot the Hyper-V server hosting VMMS, restart VMMS and Network Virtual Service Provider Windows Management Instrumentation (NVSPWMI) services or reboot Active Directory".

Lesson: Use groups, not users to grant rights.

Credit: Virtual PC Guy.

Using the Hyper-V Integration Components in WinPE

Fri, 27 Jun 2008 17:11:52 GMT

I just found a few links on adding the Integration Components to WinPE. Why would you want to do this? Simple; say you want to deploy operating systems to VM's via SCCM, WDS or ImageX. There's a lot more tools out there that will use a WinPE boot image too. You will need drivers, especially for the NIC to work. To get those, you'll need the Integration Components. Mike Sterling has documented the process.

Credit: Mike Sterling.

EDIT:

Mike has updated the script that he used in the original post.

Getting Started with Hyper-V

Fri, 27 Jun 2008 16:28:09 GMT

The links on how using Hyper-V are now live. This is a good place to start if you are new to Hyper-V. Quite honestly, it's really easy to use.

Step-by-Step Guide to Getting Started with Hyper-V

Update: Hyper-V RAM Loading

Fri, 27 Jun 2008 15:16:06 GMT

I've previously talked about my observations of how my 9GB RAM Hyper-V lab box used it's memory and how Hyper-V has a RAM overheard and how you can calculate the maximum.

Last night I upgraded the lab box from RC1 to RTM. Today, I've noticed that I have a whole lot more of RAM to play with! In fact, 1.5GB of RAM was freed up on my 9GB RAM server. Before I could only get 7GB worth of VM's up. Today, Hyper-V is looking much more efficient.

Just Upgraded To Hyper-V RTM

Thu, 26 Jun 2008 20:33:09 GMT

I've just upgraded my Hyper-V lab box to RTM. It took maybe about 10 minutes (most of that was POST during reboots) to install the update and another 5 to install the updated enhancements in 8 VM's. It's a very easy process as John Howard describes on his blog.

EDIT:

Snapshots are supported between RC1 and RTM. They are not support between either beta or RC0 and RTM.

Hyper-V Has Been Released

Thu, 26 Jun 2008 18:09:33 GMT

Bink is reporting that Hyper-V has been released to manufacturing. You can expect it to be available as a download and via Windows Updates. There should be a smooth migration from the RC1 release to RTM.

Credit: Bink.

EDIT:

This has been confirmed.

Credit: Willem Kasdorp.

EDIT

The Hyper-V team has released some details. The update will be available via Windows Updates on July 8th. The direct download will be available from sometime later today (probably midday Seattle time or 20:00pm GMT).

Hyper-V RAM Requirements Update

Mon, 23 Jun 2008 18:38:26 GMT

I've gotten feedback on my last blog update on this subject and here's the scenario:

The parent OS requires 512MB (MINIMUM) but you should allow for 2GB (recommended).
Hyper-V itself requires 300MB but it's likely the 2GB assignment will compensate for this (in most cases).
Drivers and agents on the parent might push your requirement for more than 2GB.
Each VM requires at least 32MB for the 1st GB of RAM. Each additional GB of RAM for the VM requires (at most) 8MB for each additional GB of RAM. MS say 8MB to be conservative. Only if the VM is trashing RAM will you hit this 8MB.
The second VM will require 32MB for it's first plus another 8MB (max) for each additional GB of RAM.

So here's a typical scenario:

Parent Partition: 2GB (but you might need another 200 for Hyper-V and more for drivers/agents)
2GB RAM VM: 32MB + 8MB
4GB RAM VM: 32MB + (3 * 8)MB
1GB RAM VM: 32MB

Thanks again to Dave Northey and John Howard who took the time to dig internally in MS to help me with this problem.

Credit: Dave Northey and John Howard.

Hyper-V RAM Requirements

Fri, 20 Jun 2008 22:20:32 GMT

One of my tasks today was a bit on the tough side. Following up on yesterday, I had to be able to calculate the amount of RAM required for each VM, whether it was assigned 1GB, 2GB or 4GB. Form this, based purely on RAM, I had to be able to calculate numbers of VM's I could get on a host - CPU, storage and I/O are well in hand.

This proved tough. At this point, Hyper-V is still RC1 so there's little information out there. The only result from a lot of searching was a MS page about how they virtualised 3 VM's, each with 10GB RAM, on a 32GB host. They said they reserved 2GB RAM for the parent partition. Not very useful, to be honest.

I couldn't find any more so I sent out some mails requesting some help. In the meantime I decided to do some observational testing. I ran VM's on my test host and used PerfMon to measure "Hyper-V VM VID Partition - Overhead bytes"". The overhead was as follows (rounded up):

0.5GB: .0039% of assigned RAM
1GB: .0049% of assigned RAM
2GB: .0015% of assigned RAM
3GB: .0023% of assigned RAM
4GB: .0022% of assigned RAM

OK. I loaded my VM's to 100% RAM utilisation and that overhead didn't change. That gave me something to work with but I was wondering about that 2GB for the parent. Was that official? Did the overhead for the 3 * 10GB machines come from that? Maybe it did?

This evening I got some replies. Dave Northey sent me a link to a document (Performance Tuning Guidelines for Windows Server 2008) that didn't turn up in my searches. It says:

"You should size VM memory as you typically do for server applications on a physical machine. You must size it to reasonably handle the expected load at ordinary and peak times because insufficient memory can significantly increase response times and CPU or I/O usage. In addition, the root partition must have sufficient memory (leave at least 512 MB available) to provide services such as I/O virtualization, snapshot, and management to support the child partitions.

A good standard for the memory overhead of each VM is 32 MB for the first 1 GB of virtual RAM plus another 8 MB for each additional GB of virtual RAM. This should be factored in the calculations of how many VMs to host on a physical server. The memory overhead varies depending on the actual load and amount of memory that is assigned to each VM".

So I read this two ways (assuming 2GB RAM per VM scenario):

First machine charge = 32MB overhead + 8MB. Second machine charge = 16MB overhead.
First machine charge = 32MB overhead + 8MB. Second machine charge = 32MB overhead + 8MB.

I'm assuming it's the second scenario for now. I'll chase this down next week.

I also got a response from John Howard. He said:

"Our general recommendations will be the same as for Windows Server 2008. ... minimum and recommended RAM requirements which are 512MB minimum, 2GB recommended. This is for the parent partition. Our general requirements for just the Hypervisor being launched are a little under 300MB. Any driver stacks, management applications and virtual machine memory are on top of that. In the parent partition, we consume ... RAM per virtual machine".

So being fairly conservative, it sounds like we allow 2GB for the parent, another 300MB for Hyper-V, a bit for the drivers of the parent (probably be safe within that 2GB) and then our overhead for RAM for each VM. That gives me something like this:

VM RAM (GB)	Overhead (MB)	Total MB Used
0.5	32	544
1	32	1056
2	40	2088
4	56	4152

I'll be trying to confirm this next week. For now, take my maths with a very large and un-tasty lump of salt. Any mistakes in this are mine and not those of the people I've credited. Please don't use any of this until I've confirmed it.

Credit: Dave Northey and John Howard.

EDIT:

Check out my follow-up post which confirms my understanding of the above assesment.

Hyper-V and NIC Teaming

Thu, 19 Jun 2008 11:35:35 GMT

NIC teaming, bonding, load balancing, A+B networking, or whatever you want to call it, is a core concept in highly available server computing. In Windows, we've been able to create a virtual NIC that we configured TCP in by using 3rd party drivers from the likes of HP or Intel.

The virtual network is no different. ESX can do this by using two host physical NIC's to connect a virtual switch. A VM has one virtual NIC that connects to this virtual switch and has the benefit of A+B networking. The Hyper-V virtual switch can only use one NIC. Hyper-V relies on drivers in the parent partition. You'd think "OK, lets team two physical NIC's in the parent partition and use the resulting virtual NIC to connect the virtual switch". Right now, that's not possible. HP says:

"IMPORTANT

Windows Server 2008 Hyper-V RC1 does not support the Network Configuration Utility (NIC Teaming). Deselect this component before installing the PSP components".

This is not good, not good at all. We cannot do A+B networking in Hyper-V until this changes. I'm told that MS is relying on partners, e.g. HP and Intel, to resolve this like they have done for Windows up to now. I'm really hoping that they do.

EDIT:

I got a respnse from Microsoft when I sent in some feedback on this issue. Officialy, MS does not support any kind of NIC teaming on Windows. Currently, this is no different with Hyper-V. They are relying 100% on partners such as the likes of HP, Broadcom and Intel to provide updated versions of their teaming drivers for Hyper-V. There is an opening in the parent paritition to allow partners to accomplish NIC teaming and present one virtual (teamed) NIC to a virtual switch in Hyper-V.

Hyper-V VM Loading

Thu, 19 Jun 2008 11:19:02 GMT

I'm using a lab box with 9GB RAM in it for testing to see what sort of load I can get out of a Hyper-V host. Remember that Hyper-V does not do memory over-committing like you get on ESX - who really wants paging both in the virtual machine's virtual disk and on the physical host? That sounds like server admin hell to me!

Anyway, I managed to get a series of virtual machines up and running, each with varying RAM assignment to reflect a production environment. The result was that I got 7GB of VM's up and running on the 9GB host. It appears that a full installation of Windows Server 2008 with RC1 of Hyper-V consumes 2GB RAM. That probably comes down if you use a core installation instead, which I'd recommend in a Hyper-V farm.

Cool thing here is that I noticed no drop in performance. The VM's all run quite smoothly - we're doing all sorts of things with the VM's so they are actually doing real (albeit just lab) work.

EDIT:

I followed this post up with some research on the memory overhead requirements and how Hyper-V uses RAM.

Hyper-V Test Lab Continued

Wed, 18 Jun 2008 15:35:06 GMT

I set up a few templates over the last few evenings, Windows 2008, Vista and Windows 2003. I sysprepped them today and exported the VM's. I've noticed some funnies in the exports - the confix.xml retains the path to the VHD of the original machine. This cause some problems when I copied the exports and re-imported them as new machines.

My lab machine has only so much disk and I've way more testing that I need to do. I decided to use the VHD's of my sysprepped templates as parents for differencing disks. These differencing disks are what my VM's use. The idea is that the child disk stores on the differences between the VM that I run and the parent disk of the template.

I deployed them like this:

I created a template VM, sysprepped it and saved exported it.
I put the exported VHD somewhere safe.
I created a new VM but did not create a disk in the wizard.
I returned to the settings of the VM started creating a new disk.
The new differencing VHD was stored in the \Virtual Hard Disks folder of the new VM. It's parent was the VHD of the exported template.
The new VM is powered up and runs the mini-setup wizard, i.e. I name the machine.

Simple and diskspace economic. I can deploy more VM's and they core OS is stored only once. It's perfect for a lab. Obviously it's going to be slower if running plenty of VM's off the parent. You wouldn't do this for production but it's fine for a lab.

HP NC373i Multifunction Driver, Hyper-V and VLAN Tagging

Thu, 12 Jun 2008 16:31:09 GMT

It's critical that I be able to set up separate and secured VLAN's in Hyper-V. To do this you set up an External Virtual Switch with VLAN tagging enabled.

I'm using a HP DL380 G5 with the following configuration:

Windows Server 2008 x64
HP PSP 8.0
2 * NIC's: HP NC373i Multifunction Gigabit Server Adapter (V4.1.3.0)
Hyper-V RC1

The first NIC is set up for the parent partition (that OS you install first and manages Hyper-V locally). It is attached to a normal Cisco switch port. The second NIC will be used for the virtual switch. It's connected to a Cisco switch that's configured to trunk a set of VLAN's that the VM's will run on.

I set up the VM's and tried to set up the External Virtual Switch with VLAN tagging. Problem - It failed with this error:

"Error Applying New Virtual Network Changes

Cannot enable virtual LAN (VLAN) identification. The virtual network switch is connected to a physical network adapter that does not support VLAN identification."

No matter what I did I couldn't resolve this: driver updates (N/A), reinstalling the NIC, uninstalling HP software, etc. I fired up a post on the Minasi forum and a server whiz called Willem Kasdorp sorted me out. MS had documented a workaround which my hour of googling failed to turn up. The cause of the problem was the NIC driver. The solution was to open the properties of the parent partition's NIC#2, configure the driver and set the VLAN ID to "1". Now I could create my virtual switch and everything worked perfectly.

Credit: Willem Kasdorp.

EDIT:

While having this problem I opened a call with MS via my IT Pro Momentum account. I got a quick response and they confirmed this solution. Setting the VLAN ID of the physical card to a "non zero value" resolves the issue.

Hyper-V and VLAN's

Wed, 11 Jun 2008 15:25:24 GMT

Following up on my recent posts on Hyper-V, I thought I'd write up a quick post on setting up multiple VLAN's in Hyper-V. In my research I found these posts:

They pretty much say everything that's needed so you don't need any whitepapers from me - I'm sure you're glad to hear!

The concept is that you create a trunk on any physical switch ports that are connected to your VM's. You then publish the required VLAN's to that trunk (forgive me - I'm not a Cisco guy; I just ask a local expert for what I want and he does a great job in doing it). You can then VLAN tag either your virtual network in Hyper-V (if everything on that network, i.e. on that physical NIC, should be in the VLAN) or you assign VLAN tags to the VM's.

This is quite secure. You're pretty much doing what you do in VMware ESX. The machines with different VLAN tags cannot talk directly to each other without going through either a router or a firewall that connect the VLAN's. The VM's can co-exist on a VLAN with physical hosts.

The thing you've got to watch out for is that the NIC associated with the virtual switch must support VLAN's and accept packets with VLAN tags.

Credit: Virtual PC Guy.

BTW: I highly recommend that blog because it's full of great information and sample VBS/Powershell scripts.

HP and Hyper-V

Tue, 10 Jun 2008 21:48:26 GMT

I installed Hyper-V on a decent spec HP DL380 G5. Before I did, I read a guide on configuring a HP Proliant for Hyper-V. It'll guide you on how to enable virtualisation assistance in the CPU and enabling DEP (both in the BIOS). HP also has a Hyper-V web page.

Just Deployed Hyper-V

Fri, 06 Jun 2008 12:22:26 GMT

I just deployed RC1 of Hyper-V for the first time. Damn, it was easy. Install the OS, download the Hyper-V RC1 update and install it, add the Hyper-V role and you're all ready to create VM's. You need one NIC per virtual switch and at least one NIC for the parent partition.

One annoyance is that you cannot have ontrol over the mouse if you RDP into the Hyper-V console until you've installed the integration services. This is possible on Windows Server 2008 and Windows Server 2003 with SP2 - ah ... you have to install the OS and then the SP before you can use your mouse.

The solutions are to use the Remote Hyper-V admin tool for Vista or aparently to RDP in from W2008. Eek. What if your Hyper-V servers are remotely located? I don't want to use an MMC over a WAN link. That sucks! RDP is the solution of choice.

Still ... I like Hyper-V so far.