Can you try setting the following in hadoop-site.xml at the name node and
see if the time comes down to around a minute
<property>
<name>heartbeat.recheck.interval</name>
<value>1</value>
</property>
This effectively
On Thu, Jan 22, 2009 at 9:42 AM, Hargraves, Alyssa <[email protected]> wrote:
> I was following the steps at <http://wiki.apache.org/hadoop/FAQ#17> to do
> the decommission. However, you have to be patient with it since it seems to
> take a long time. If it took 3-5 minutes with my nodes that have no data
> and no jobs running, I can't imagine how long it would be for a real
> cluster. One thing that I had trouble with originally was the fact that it
> doesn't seem to work if your replication is set to be same as your number of
> machines (since I was just testing things, I had replication set to 2 with 2
> machines, but that's not a good real-world example).
>
> The problem I'm having though (from Jeremy's reply earlier it sounds like
> he misinterpreted it) isn't how long it is taking for the node to go from
> decommissioned to being recognized by the master as dead. Whether or not
> it's recognized as dead isn't something that matters for what I'm doing.
> The real problem is that going from the In Service to Decommissioned state
> is taking forever. Decommission In Progress lasts 3 to 5 minutes despite
> the fact that there aren't jobs or data on those nodes. If anyone else has
> any idea why that might be (I can see why it would take time if there are
> jobs or data, but not otherwise) please let me know.
>
> - Alyssa
> ________________________________________
> From: Rob Hamilton [[email protected]]
> Sent: Thursday, January 22, 2009 12:26 PM
> To: [email protected]
> Subject: RE: Decommissioning Nodes
>
> I wasn't able to get decommissioning to work at all and found that just
> taking the node down got it out of the cluster. What version are you running
> and how are you initiating the decommissioning?
>
> -Rob
>
>
> Rob Hamilton - VP Network Operations
> P +1 (410) 379-2195 x 240
> E [email protected]
> 6085 Marshalee Drive, Suite 210
> Elkridge, MD 21075
>
>
> -----Original Message-----
> From: Hargraves, Alyssa [mailto:[email protected]]
> Sent: Wednesday, January 21, 2009 7:35 PM
> To: [email protected]
> Subject: Decommissioning Nodes
>
> 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
>
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--
Kumar Pandey
http://www.linkedin.com/in/kumarpandey
