Fs image is a directory of name node.It contains the complete state of file system at a point in time.Fs image represents the file system state after all modifications up to a specific transaction id.
The function which is called for splitting the user data is Mapreduce.
3.How to Modify the heartbeat and block report time interval of datanode?
dfs.heartbeat.interval default value of 3 determines the datanode heartbea interval in 3 seconds
dfs.blockreport.intervalMsec with default value of 21600000 determines blocking time in ms.
Referred from Google.
4. Lifecycle of SNN
Secondary Name node is having a backup of metadata.
It takes the responsibility of merging of editlog with fs image from namenode.
It has a checkpoint directory.
5.If 2tb is given what is the maximum size metadata will genertae
The data which is generated will be in kb.