You administer a server that runs Windows Server 2012 R2 with the Hyper-V role installed. You plan to deploy
a new virtual machine (VM to the server. The data stored by the VM doubles each month.
You have the following requirements:
The virtual hard disk (VHD) must minimize the storage space requirements. Changes to the VHD must NOT
require user intervention.
You need to create the VHD. What should you create?
A.
a dynamically expanding file that uses the VHD file format
B.
a file that uses the VSV file format for the dataLUN
C.
a differencing file that uses the VHD file format
D.
a differencing file that uses the VHDX file format
Why not A: a dynamically expanding file that uses the VHD file format?
I’m guessing because you have to manage the limit of a dynamic disk, while a differencing file will continue to expand until the physical disk is full.
Seems like a poor question to me.
You can use dynamic with max disk quota set to max of your HDD, so do not to touch it anyway.
Dif disk may store data twice in some cases, so it does not minimize storage!
A vote for A
Answer is C
Differencing
A Differencing VHD is a so-called child disk based on a linked parent disk. Creating a child disk by specifying the parent disk establishes the parent-child relationship. Since then a child disk stores those changed/modified data of the parent disk, i.e. the write operations to the parent disk.
NOTE: The question says: ” The data stored by the VM doubles each month” , it’s making reference to the data alone, not that the data generated will be saved inside the same VHD. Because of that I thought it could be a Dynamically expanding disk. –KameX–
I think it’s A
A differencing disk has a link to a parent disk. So you always have 2 disk’s. The parant disk white the actuale size + the differencing disk white al the delta data.
As data are written into a Dynamic VHD, the total size of the VHD will grow accordingly
Example
differencing
-VHD (30GB) + differencing disk (from 0GB to 30GB) = min 30GB, max 60GB
Dynamic VHD
-VHD dynamic (30GB) = min 0GB, max 30GB
http://technet.microsoft.com/en-us/library/cc708315(v=ws.10).aspx
The answer is A as a Dynamically Expanding disk will minimize storage space requirements.
I agree the answer is A. It minimizes storage requirements and grows without intervention.
A differencing disk has a different purpose, to record changes to another VHD. And in this case, it has a limitation – a differencing disk can only grow as large as the parent disk to which it is associated, whether that parent disk is a fixed disk or dynamic disk. So there is no benefit of using a differencing disk.
In addition, other than performance and reliability, there is no feature advantage between a differencing VHD or VHDX, so both C and D answers are effectively the same, which pretty much rules out C and D as an option. The question doesn’t clearly say whether the parent disk, if one exists, is VHD or VHDX.
Also, because the differencing disk is no bigger than the parent disk, if you use a dynamically expanding disk as the parent disk and a differencing disk, you are then doing both answers A and C, and only one answer is allowed.
The question is poorly asked.
The correct answer is C, just because of the “Changes to the VHD must NOT
require user intervention” argument.
If you create a dynamically expanding file that uses the VHD file format you must configure a maximum size of the file, this being the maxim storage you have available at the moment you create the VHD. Even if you monitor the increase in the file and add additional storage, the VHD still has the same limit, so an “user intervention” is required to change the VHD limits to accommodate the new available storage.
While a differencing file will grow until the storage is full, if you increase the available storage, no intervention to the VHD file is required, as the differencing file will continue to grow in the newly available storage space.
Please correct me if I’m wrong!
A differencing disk still has a limit. That is, logically seen from the OS it has a fixed size > the disk can get full.
You can just set the dynamically expanding disk on the maximum disksize (way bigger than the actual phyical disksize you might have) and never have to worry about it.
Definitely A.
The correct answer is A. Answers C and D do not minimize the storage space requirements, as data can possibly be stored twice. For those who stated that the correct answer would be C, then you could just as well have chosen answer D, as they are effectively the same, which is another clue that answers C and D are both not correct. As for the requirement that changes to the VHD must not require user intervention, the emphasis here lies on the word “user”. The user will not have to intervene. The administrator might, but that is not a requirement.
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