I am doing some performance testing in HADOOP. But while testing, I faced a
situation. I need your help.
My HADOOP cluster :
6 Datanodes, 1 Namenode, 2 Clients.
Replication factor = 3
2 clients write a file(put operation) whose size is 2 x block size.
DFS.DATA.DIR in each Datanodes is equal and is same as block size. That
means each Datanodes stores a single block.
Now, if 2 clients simultaneously reads the file( get operation),
Will 2 clients read 2 blocks from different Datanodes ?
Or they will read from the same datanodes?
Does Namenode know which Datanode is busy and which one is idle?
What I am trying to find is that...
Is it possible to decrease the read time by increasing replication factor?
I have attached an image to better understand my question. Kindly take a
look. Thank you. And if possible please give references.
bharath vissapragada 2013-01-23, 09:44