deploy rack concept in cluster

Hi Team

Below is your answer:

1. what would be the best scenario to deploy the rack in the cluster?

Ans. When you have huge read/writes going on DN and have huge no of DN then toreduce the network traffic while file read/write, which improves the cluster performance
2. will this rack deployment cause unavailability in the cluster?

This rack will contain equal no of DN suppose you have 9 DN with 3 rack then each rack will have 3 DN now block placement will be 1-2 Block in each rack with different DN so suppose one rack will fall then you will have another 2 rack to take care of read/write

3. what are the “strengths” and “weaknesses” when deploying the rack in the cluster?

Ans.

Strength: High Availabilty , Performance improvement

Weakness: not seen any with RF=3 blocks but if you have less than 3 then there might be scenario that 2 blocks will be on same rack but in different DN if that rack falls then it will cause unavailabilty

@yagoaparecidoti 

then one each rack will have 2 replica/each rack in different DN so if one rack goes down other will be available but its better to have 3 rack with 7 DN each as per your scenario

@Asfahan 

when implementing the rack concept, isn't the distribution of blocks 1 block for rack_01 and 2 blocks for rack_02?

yes it will if you will my 2nd last comment i mention the same that 1 blocks will be in rack1 and 2 blocks will be in rack2 on different DN if you will have 3 racks then either 1 blocks each rack or same 1 block and 2 blocks in each rack