You have a server named Server1 that runs Windows Server 2012 R2.
You plan to create a storage pool that will contain a new volume.
You need to create a new 600-GB volume by using thin provisioning. The new volume must
use the parity layout.
What is the minimum number of 256-GB disks required for the storage pool?
A.
2
B.
3
C.
4
D.
5
Explanation:
Based on the RAID calculators, in order to do a parity drive (raid 5) of 600GB will require at
least 4 drives.
References:
http://technet.microsoft.com/en-us/library/hh831391.aspx
http://www.ibeast.com/content/tools/RaidCalc/RaidCalc.asp
http://www.raid-calculator.com/default.aspx
https://www.icc-usa.com/raid-calculator
” … 600 GB thin provisioning”
isn’t it enough to start with 3 x 250 = 500 GB ?
Answer B.
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Good point Franz, I would also have chosen C.
B is the right answer.
https://technet.microsoft.com/en-us/library/jj822938.aspx
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Agree:
Parity – This is a striped set with distributed parity by striping data and parity information across multiple disks, similar to RAID 5. It increases reliability with reduced capacity. This configuration requires at least three disks to protect data from a single disk failure, and cannot be used in a failover cluster.
http://blogs.technet.com/b/yungchou/archive/2012/08/31/windows-server-2012-storage-virtualization-explained.aspx
The answer is B. (!)Thin(!) provisioned means ONLY virtual limits (MAX 64 TB within 2012 R2)
(!)Thick(!) provisioned the answer would be C.
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The question clearly says:
“You need to create a 600GB volume”.
Creating a 500GB volume is not correct.
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My choice would be C. 4
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Answer is B.
You need 3 disks minimum because of parity.
You do not need to allocate more because of the “thin” provisioning type of the Virtual Disk.
You first create a storage pool with 3 disks.
You then create a new Virtual Disk, and there you select a “Storage Layout” selecting “Parity”,then Provisioning type = “thin”. and assign (as it is “thin provisioned”) the size that you want.
Then you create the volume (selecting the new disk), and assign the space and a letter (optional). You give it a file system, and that’s it.
If you need to add a new disk to the storage pool (because of the “thin” provisioning), you can do this by right clicking on the storage pool, and selecting “Add physical disk”.
Confusing thing is that the “physical disk” can well be a virtual disk, but it works the same.
This was tried (and working) on a 2012 R2 lab.
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I just tested this in a 2012r2 lab machine.
Added 3 40 disks to a Storage Pool. 3x40GB in RAID5 is 80GB.
Created a new virtual disk on the storage pool
Selected Parity for Storage Layout
Specified Thin Provisioning
Set disk size to 200GB
Created
New volume wizard popped up
Went through new volume wizard, specified size of 200GB
New volume is in service
B is correct.
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Thanks For that Answer Nick. saves me testing it
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I agree, B is the correct answer, not C.
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So what is the correct answer? like what would be the answer they would accept on exam?
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Probably B, but it is bad practice to do so.
You should only “over-subscribe” on pool that host more than 1 virtual disk. in this scenario you’d immediately have a problem when the disk reached his size (or rather 2×256) limit.
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As per the bellow Thin Provisioning definition answer should/can be B. notice the “over-subscribing” feature specifically for the question scenario
“Thin provisioning of a virtual disk optimizes the utilization of available storage in a storage pool via over-subscribing capacity with just-in-time allocation. In other words, the pool capacity used by a virtual disk with Thin provisioning is according to only the size of the files on the virtual disk, and not the defined size of the virtual disk. While Thin provisioning offers flexibility and optimization, the other virtual disk provisioning scheme, Fixed, is to acquire specified capacity at disk creation time for best performance.”
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Answer is C:4
If you use ‘ http://www.raid-calculator.com/default.aspx ‘ you can work out the capacity of 3 disks at 250gb in size using raid 5(parity)
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That would be correct if it were traditional RAID 5. But being that it is a THIN provisioned disk, you don’t have to meet the 600 GB size. You need 3 drives to meet the parity requirement. After that, you could pretty much use any size drives you want with a thin provision (granted, you’ll be over subscribed).
You can make a 600 GB thin provision using 3 x 250 GB, 3 x 100 GB, 3 x 72 GB, etc.
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Parity requires 3 disks minimum. It’s thin provisioning, so you don’t need all of of the 600GB to be available immediately, so answer is B, 3 disks.
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The answer is C:4.
Remember that you lose a disk when you are using Raid 5 so if you were to use 3 disk technically it is 768gbs, but 256GBs of the volume is for Parity, so that would only give you 512GBs because you lose a disk. With 4 disk you will end up with 768gbs which is more then the 600GBs required for the configuration. Although 4 disk equals a TB in the case, you lose a disk to parity.
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The answer is B
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Answer Is (B) (3 Harddisk)
As of the Red Hat Enterprise Linux 6.4 release, logical volumes can be thinly provisioned. This allows you to create logical volumes that are larger than the available extents. Using thin provisioning, you can manage a storage pool of free space, known as a thin pool, which can be allocated to an arbitrary number of devices when needed by applications. You can then create devices that can be bound to the thin pool for later allocation when an application actually writes to the logical volume. The thin pool can be expanded dynamically when needed for cost-effective allocation of storage space.
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Logical_Volume_Manager_Administration/thinprovisioned_volumes.html
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Thanks Shane – used the capacity calculator & saw that 3 x 256GB disks with RAID 5 = 512 GB (600GB)
HENCE the correct answer is C!
http://www.raid-calculator.com/default.aspx
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Answer A
I tested on lab with Vm test
I created a storage poll with 2 * 256GB
Created a vsdisk, Layout : Mirror, provisioning type : Thin, size 1000 GB
Created a volume on the Vdisk size 1000 GB
Assigne a letter
And that works….
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