Hey Alyssa, If one of those datanodes down, a few minutes will pass when master discover this phenomenon. Master node takes those nodes which have not send heatbeat for quite a while as dead ones.
On Thu, Jan 22, 2009 at 8:34 AM, Hargraves, Alyssa <aly...@wpi.edu> wrote: > Hello Hadoop Users, > > I was hoping someone would be able to answer a question about node > decommissioning. I have a test Hadoop cluster set up which only consists of > my computer and a master node. I am looking at the removal and addition of > nodes. Adding a node is nearly instant (only about 5 seconds), but removing > a node by decommissioning it takes a while, and I don't understand why. > Currently, the systems are running no map/reduce tasks and storing no data. > DFS Health reports: > > 7 files and directories, 0 blocks = 7 total. Heap Size is 6.68 MB / 992.31 > MB (0%) > Capacity : 298.02 GB > DFS Remaining : 245.79 GB > DFS Used : 4 KB > DFS Used% : 0 % > Live Nodes : 2 > Dead Nodes : 0 > > Node Last Contact Admin State Size (GB) Used (%) > Used (%) Remaining (GB) Blocks > master 0 In Service 149.01 0 > 122.22 0 > slave 82 Decommission In Progress 149.01 0 > 123.58 0 > > However, even with nothing stored and nothing running, the decommission > process takes 3 to 5 minutes, and I'm not quite sure why. There isn't any > data to move anywhere, and there aren't any jobs to worry about. I am using > 0.18.2. > > Thank you for any help in solving this, > Alyssa Hargraves -- My research interests are distributed systems, parallel computing and bytecode based virtual machine. http://coderplay.javaeye.com
