Problem with hadoop decommission

[trang van anh]

Dear all,

I setup hadoop cluster with following struture
1 Namenode named server1;
4 datanodes named server1,server2,server3,server4.

Hadoop cluster capacity: 128G
DFS used : 49G
i want to detach server1 from cluster but time consumed slowly. I don't 
know why?

Any idea for me

Thanks in advance.