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Currently Taking NCA 5.20 Course

  • 13 October 2022
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Hi everyone, I am currently taking NCA 5.20 course and while I was doing the quizzes, I ran into this question which I could not figure out why the answer is 5tib. Anyone could help and explain to me. Thank you very much!

Your current storage pool is 10TiB. With 5 storage containers configured and a Replication Factor of 2, what is the size of each storage container?

  1. 2TiB
  2. 1TiB
  3. 10TiB
  4. 5TiB Answer
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Best answer by JeroenTielen 14 October 2022, 08:39

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9 replies

Userlevel 2
Badge +6

I believe 3. 10 TiB

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I believe 3. 10 TiB

The answer is 5 TiB. But I don’t understand how to calculate..

Userlevel 4
Badge +5

If the storage pool is 10TiB and the Storage Container has replication factor 2 (the data is 2x in the cluster) then the available space is 5TiB on the RF2 containers. 

Keep in mind that 5TiB is not available in each storage container. It is the total available in the cluster. So if 1 container had 4 TiB in use, then there is 1TiB available across all containers. 

When there is reservation applied or replication factor 3 the answer is different but that is not the case in this question. 

Userlevel 2
Badge +3

 10tib as physical capacity than considering RF2 logical usable capacity will be 5TB

 

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If the storage pool is 10TiB and the Storage Container has replication factor 2 (the data is 2x in the cluster) then the available space is 5TiB on the RF2 containers. 

Keep in mind that 5TiB is not available in each storage container. It is the total available in the cluster. So if 1 container had 4 TiB in use, then there is 1TiB available across all containers. 

When there is reservation applied or replication factor 3 the answer is different but that is not the case in this question. 

I still don’t understand this.

Badge

If the storage pool is 10TiB and the Storage Container has replication factor 2 (the data is 2x in the cluster) then the available space is 5TiB on the RF2 containers. 

Keep in mind that 5TiB is not available in each storage container. It is the total available in the cluster. So if 1 container had 4 TiB in use, then there is 1TiB available across all containers. 

When there is reservation applied or replication factor 3 the answer is different but that is not the case in this question. 

I still don’t understand this. How do I calculate the size of each storage container?

 

Userlevel 4
Badge +3

Storage pool - Full physical amount of your cluster. It operates with physical capacity, and it’s 10TiB (rough - the sum of all your disks in the cluster).
Storage container (where VMs are located) operates with amount of Physical capacity divided by Replication Factor (to keep your data safe). It calls Logical Capacity. In your case, you need to divide 10 TiB by your Replication Factor. 10TiB / 2 = 5TiB
So while there is no reserve on Storage containers and no used space, each of 5 containers can grow up to 5 TiB if another 4 containers will not use any space.

 

 

Userlevel 4
Badge +5

If the storage pool is 10TiB and the Storage Container has replication factor 2 (the data is 2x in the cluster) then the available space is 5TiB on the RF2 containers. 

Keep in mind that 5TiB is not available in each storage container. It is the total available in the cluster. So if 1 container had 4 TiB in use, then there is 1TiB available across all containers. 

When there is reservation applied or replication factor 3 the answer is different but that is not the case in this question. 

I still don’t understand this.

Lets try again 😉 The storage pool has the physical amount of storage available. So 10TiB. From the storage pool you create storage container with replication factor 2. Storage containers is logical so (RF2) 5TiB. It doesnt matter how many storage containers you create as the total logical space is 5TiB. 

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If the storage pool is 10TiB and the Storage Container has replication factor 2 (the data is 2x in the cluster) then the available space is 5TiB on the RF2 containers. 

Keep in mind that 5TiB is not available in each storage container. It is the total available in the cluster. So if 1 container had 4 TiB in use, then there is 1TiB available across all containers. 

When there is reservation applied or replication factor 3 the answer is different but that is not the case in this question. 

I still don’t understand this.

Lets try again 😉 The storage pool has the physical amount of storage available. So 10TiB. From the storage pool you create storage container with replication factor 2. Storage containers is logical so (RF2) 5TiB. It doesnt matter how many storage containers you create as the total logical space is 5TiB. 

Are the containers dynamically allocated by default?