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Windows 8 Storage and Hyper-V – Part 2: VHDX and PowerShell
Jan 24th
This blog is part of a series that started with Windows 8 Storage and Hyper-V Part 1 – Introduction:
http://www.hyper-v.nu/archives/hvredevoort/2012/01/windows-8-storage-and-hyper-v-part-1-introduction/
VHD HISTORY
If you have been working with any of the Microsoft virtualization products, you are familiar with the Virtual Hard Disk format. VHD was introduced with Microsoft’s acquisition of Connectix and their Virtual PC product in 2003. Seven years ago Microsoft decided to make the VHD Image Format Specification available to third parties under the Microsoft Open Specification Promise.
In June 2005 Microsoft promised that the VHD file format would have a future well beyond the then prevalent virtualization products ….. and boy did they keep their promise!
The Microsoft VHD file format specifies a virtual machine hard disk that can reside on a native host file system encapsulated within a single file. The format is used by Virtual PC 2007, Virtual Server 2005 R2 and Hyper-V and the format will be used by future versions of Microsoft Windows Server that includes hypervisor-based virtualization technology. Beyond that, the VHD format is broadly applicable, because it is agnostic to the virtualization technology, host operating system, or guest operating system with which it is used.
Customers and partners who invest the VHD file format will have a clear path forward to future Windows virtualization technologies. In addition, Microsoft plans to design its systems management tools around the VHD file format for improved patching and manageability.
Since the release of Windows 7 and Windows Server 2008 R2, the VHD format became even more versatile when Microsoft promised not only to standardize the variety of container files, but also introduced native VHD. This technology made it very easy to boot from VHD and have multiple operating systems on one machine. Since then VHD’s could not only be created via the Hyper-V manager but also via the inbox Disk Manager and Diskpart. Because the VHD format was opened up a multitude of VHD tools surfaced (vhdtool, disk2vhd, wim2vhd and many more). There was no easy way to just mount the VHD from the command line so 3rd parties jumped on this as well. I should not forget to mention James O’Neill’s awesome Hyper-V PowerShell Management Library which he created when he still worked for Microsoft.
The VHD related commands in that library are:
Get-VHDDefaultPath, Get-VHDInfo, New-VHD, Compact-VHD, Test-VHD, Convert-VHD, Merge-VHD, Mount-VHD, Unmount-VHD
VHDX
During the \\build conference we learnt that Microsoft will introduce a new advanced version of the Virtual Hard Disk format called VHDX in Windows 8 (both client and server). What do we currently know about this VHDX?
HP P6000 EVA and Microsoft Hyper-V
Jun 21st
In a recent technical brief HP zooms in on the new HP P6000 Enterprise Virtual Array combined with
Hyper-V. The paper discusses a number of topics related to HP’s new storage array:
-
Thin Provisioning
-
LUN Migration
-
FC, iSCSI and FCoE
-
Performance
The speed of creating a Fixed Sized VHD
Jun 1st
Today I had to deliver a few 500GB Fixed Sized VHD’s in our Nobel Hyper-V Cloud Datacenter. The job had to be finished in a few hours involving provisioning the LUN, presenting them to the hosts, creating the VHD, adding the VHD to the Virtual Machines and prepare/format the disks for final use within the VM. Of course this had to be done without downtime to the users. Another very easy job but let me warn you: “It takes a bit of time!”
The VM’s involved were two Exchange 2010 DAG servers, the one in our Hilversum datacenter on an HP BL460G6 blade server connected to HP EVA enterprise grade storage with dozens of FC 450GB 15K disks and the other in the customer’s datacenter in Amsterdam, which serves as a DR site. The DR site has no HP EVA storage and there is no replication. We use a few single Hyper-V ProLiant ML370 servers with a bunch of local 1TB FATA storage. We backup to a local DPM2010 server in Hilversum and replicate that to a second DPM2010 server in Amsterdam. So recovery can be relatively fast.
How about speed?
Creating a 500GB fixed sized VHD on the EVA storage took only 49 minutes or almost 10 times faster.
Creating a 500GB fixed sized VHD on the Direct Attached Storage (DAS) on the recovery Hyper-V Server where the DR instance of the Exchange 2010 VM lived took a little over 8 hours.
Of course this is not a problem but very costly if the customer has to pay by the hour.
I was happy to have started the fixed disk creation the evening before so when I looked this morning both VM’s were ready and waiting to be used.
How to defrag a Hyper-V R2 Cluster Shared Volume
May 31st
Recently I was asked to describe the correct procedure for defragmenting Cluster Shared Volumes on a Hyper-V R2 cluster. This is not really a very complicated task but if you have never had the opportunity to give it a try, this blog post will offer you the exact steps using PowerShell.
Case
Let’s start with a case description: the System Center Operations Manager Windows Management Pack is reporting “Logical Disk Fragmentation Level is high” for your Hyper-V R2 servers.
A Cluster Shared Volume (CSV) contains the configuration, virtual hard disk and snapshot files of multiple Hyper-V guests. Notably fragmentation of the large VHD files deserve your attention.
Fragmentation of these files can become a problem because the disk head needs to use an increasing number of seeks, lowering the throughput and thus the perceived performance of the guest as a whole.
On the other hand, NTFS has become more and more efficient in recent OS versions and fragmentation need not always have a severe impact on performance.
Analysis
CSV is a distributed orchestration layer on top of NTFS (implemented as a file system filter driver) and for fragmentation it takes advantage of all the NTFS techniques. The advantage of this design is that all disk management tools which have been written for NTFS continue to work, including a variety of defrag tools.
SCVMM 2012 – Preparing the Host Profile
Apr 18th
In the previous blogs I have explained how to create Run As Accounts & Profiles. I also discussed Out of Band Management and specifically how to Add the HP iLO2 OOB provider to SCVMM 2012. In this blog I focus on another preparatory step before we can start our Bare Metal Deployment and Cluster Creation: Preparing the Host Profile.
The Host Profile is like a combination of the Hardware Profile and OS Profile in SCVMM 2008 R2 but intended for defining the physical server rather than the virtual machine. Again a wizard is available to define such a Host Profile which is relatively straightforward:
- General: Host Profile Name & Description plus location of the VHD file to be used as the base image for the operating system
- Hardware Configuration: Selection of the Management NIC with a choice of DHCP or static IP address; Partition and Disk Configuration and Driver Options (for injection of a specific set of (filter) drivers
- OS Configuration: similar to the OS Profile in SCVMM 2008 R2 describing OS name, Run As Profile, Admin Password, Identity Information, Product Key, Time Zone and Scripts
- Host Settings: for adding the virtual machine placement paths
The preparation of the Host Profile starts off by clicking on the Library wunderbar, expanding Profiles and right-clicking Host Profiles: Create Host Profile.
Presenter @ ExpertsLive on June 16th 2010
Apr 17th
I will be presenting at ExpertsLive which is held in Nijkerk, the Netherlands on June 16th 2010.
Experts Live is a knowledge event around Microsoft Infra & Security, Unified Communication, Virtualization and Management with Microsoft System Center.
My talk will be called Hyper-V R2 Hotspots zooming in on Hyper V R2 Clusters, Cluster Shared Volumes, Live Migration, Direct I/O, Dynamic Storage, Direct Memory and VHD Tooling.
Proud to say that my company Nobel is one of the main sponsors of the event, along with Citrix and PQR.
The event has free admission but requires registration via http://expertslive.nl/
Virtual Hard Disk Performance
Mar 18th
Liang Yang and Anthony F. Voellm have published an interesting article (March 2010) on the awesome performance improvements attained with the Microsoft VHD format in Windows Server 2008 R2, both in native VHD and Virtual Machine VHD.
The article describes the VHD format, compares VHD performance in Windows Server 2008 and in Windows Server 2008 R2, Native and Virtual Machine VHD performance and explains the difference in performance between fixed sized, dynamically expanding and differencing disks.
Supported and practical limits of VHD’s
|
Virtualization Feature |
Windows Server 2008 Hyper-V(RTM) |
Windows Server 2008 R2 |
|
Nested Depth (VHD in VHD) |
0 |
2 |
|
Default VHD Block Size |
512KB |
2MB |
|
Minimum VHD Size |
3MB |
3MB |
|
Number of Attached VHDs |
Limited by the virtual bus (64) |
Limited by the number of disks Windows allows |
|
Max Differencing Chain Length |
Effective = 8 Supported = 50 |
Effective =1024 Supported = 1024 |
|
Max Fixed Sized VHD Size |
2048GB(2040G via Hyper-V Manager) |
16TB(2040G via Hyper-V Manager) |
|
Max Dynamic VHD Size |
2040GB |
2040GB |
|
Max Differencing VHD Size |
2040GB |
2040GB |
For full article please go to this url:
http://download.microsoft.com/download/0/7/7/0778C0BB-5281-4390-92CD-EC138A18F2F9/WS08_R2_VHD_Performance_WhitePaper.docx)
VHD Attach
Nov 13th
Here’s a nice little tool to atttach and detach VHD files. It can be used with Windows 7 and Windows Server 2008 R2:
http://www.jmedved.com/?page=vhdattach
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