The memory consumption of hadoop's namenode?

Question

Can anyone give a detailed analysis of memory consumption of namenode? Or is there some reference material ? Can not find material in the network.Thank you!

Answer 1

Example calculation

200 node cluster
24TB/node
128MB block size
Replication factor = 3

How much space is required?

# blocks = 200*24*2^20/(128*3)
~12Million blocks
~12,000 MB memory.