Exam Prep for 70-659 Part 6: Configuring Child Storage

As I wrote in an earlier post, there is no better time to write your exam for 70-659 Windows Server 2008 R2, Server Virtualization, than now and particularly before May 31, 2012. So to aid in that endeavour, Joseph Yedid, an IT specialist with Enhansoft in Ottawa, has put together a series of posts focused on getting IT folk ready to pass this exam. Joseph writes his blog at www.josephyedid.com but has allowed me to repost this series here.

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Configuring Child Storage

So what is dynamic VM storage? Simply put, dynamic VM storage is a new capability found in Windows Server 2008 R2 that allows for installation and removal of ISCSI storage in a virtual machine. In order for this to function, the integration services must be installed on the guest OS.

Differencing disks are a type of VHD. Best practice states that they should not be used in production however, they are ideal for a lab environment. Differencing disks rely on a “parent” or master (template) VHD. “Child” VHDs are created based on the parent/master VHD. If the connection is broken between parent and child, the “child” VHDs will not work. Differencing disks have similar properties of dynamic disks; they start out small and grow as used or needed.

Pass-through disks are unformatted LUNs. No VHD is created. They can be assigned to a VHD and are presented as physical storage. Their purpose is to help off-load I/O intensive functions, for example an SQL database. In this manner, they gain 100% of the potential storage performance. They can have storage greater than 2048GB. A drawback of pass-through disks is that they don’t have the mobility of VHDs.

Snapshots can be created in a few ways; in Hyper-V Manager, using the VM Connection tool, and in VMM. In Hyper-V Manager, in the setting of a VM, you can specify where the snapshot will be stored, under Snapshot File location. Using the VM Connection tool for taking snapshots, you will be presented with a dialogue box for a file name of the snapshot, this also goes for VMM. Taking snapshots creates the following files: snapshot differencing disk (.AVHD), VM memory contents (.BIN), VM saved state (.VSV), and VM configuration (.XML). Snapshots can only be taken when virtual machines are in the following states: running, saved, or shutdown.

VM GUIDs are associated with the VM worker process, vmwp.exe. Using the Task Manager, you can see what GUID is associated with which vmwp.exe. To do this, open the Task Manager, select the Processes tab and add the Command Line column. Doing this will allow you to manage the GUIDs.

One method to managing LUNs is the ISCSI software target, now a free download from Microsoft. It can be found here. With the ISCSI software target you can create and manage LUNs quickly and easily.

Editing VHDs is done through either Hyper-V Manager or VMM. Whichever you choose, the options will be the same. To edit a VHD, simply open the settings of the VM.

How do you copy a physical disk to a VHD? At this point there is only one way, and that is to use Disk2VHD. This is a tool created by Mark Russinovich and Bryce Cogswell of Microsoft’s Sysinternals. Disk2VHD will copy the contents of a selected volume and copy them into a VHD file. Disk2VHD can be found here.

Read the full series >>

Joseph-1Joseph Yedid is an IT specialist working at Enhansoft a company based in Ottawa, Canada, that develops products and services to extend the value of System Center Configuration Manager 2007 (SCCM) and System Center Configuration Manager 2012. He is an avid user of technology and is certified in many areas of Microsoft infrastructure technologies. He is MCTS and MCITP certifed - Windows Server 2008 and Microsoft Vista/Windows 7. Other interests revolve around virtualization technologies, System Center and Private Cloud. Joseph is a member and on the executive of the Ottawa Windows Server User Group.

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