Re: Is it possible to set how many map slots to use on each job submission?

2012-01-18 Thread Arun C Murthy
The CapacityScheduler provides exactly this. Setup 2 queues with appropriate capacities for each: http://hadoop.apache.org/common/docs/r1.0.0/capacity_scheduler.html Arun On Jan 17, 2012, at 10:57 PM, edward choi wrote: Hi, I often run into situations like this: I am running a very heavy

Re: NameNode per-block memory usage?

2012-01-18 Thread prasenjit mukherjee
Does it mean that on an average 1 file has only 2 blocks ( with replication=1 ) ? On 1/18/12, M. C. Srivas mcsri...@gmail.com wrote: Konstantin's paper http://www.usenix.org/publications/login/2010-04/openpdfs/shvachko.pdf mentions that on average a file consumes about 600 bytes of memory in

Re: NameNode per-block memory usage?

2012-01-18 Thread prasenjit mukherjee
Does it mean that on an average 1 file has only 2 blocks ( with replication=1 ) ? On 1/18/12, M. C. Srivas mcsri...@gmail.com wrote: Konstantin's paper http://www.usenix.org/publications/login/2010-04/openpdfs/shvachko.pdf mentions that on average a file consumes about 600 bytes of memory in

Re: How to find out whether a node is Overloaded from Cpu utilization ?

2012-01-18 Thread John Meagher
The problem I've run into more than memory is having the system CPU time get out of control. My guess is that the threshold for what is considered overloaded is going to be dependent on your system setup, what you're running on it, and what bounds your jobs. On Tue, Jan 17, 2012 at 22:06,

Receive with immediate delete

2012-01-18 Thread Daniel Baptista
Hi, I have a small cluster of 4 datanodes, all datanodes are running version 0.20. I am trying to decommission one of the nodes however I am seeing the DFS usage fluctuate from 2.07 - 2.09 GB and then it drops back down to 2.07, the block count also fluctuates in a similar pattern. It has been

Re: Using S3 instead of HDFS

2012-01-18 Thread Mark Kerzner
It worked, thank you, Harsh. Mark On Wed, Jan 18, 2012 at 1:16 AM, Harsh J ha...@cloudera.com wrote: Ah sorry about missing that. Settings would go in core-site.xml (hdfs-site.xml will no longer be relevant anymore, once you switch to using S3). On 18-Jan-2012, at 12:36 PM, Mark Kerzner

Re: Using S3 instead of HDFS

2012-01-18 Thread Matt Pouttu-Clarke
I would strongly suggest using this method to read S3 only. I have had problems with writing large volumes of data to S3 from Hadoop using native s3fs. Supposedly a fix is on the way from Amazon (it is an undocumented internal error being thrown). However, this fix is already 2 months later

Re: Using S3 instead of HDFS

2012-01-18 Thread Mark Kerzner
Awesome important, Matt, thank you so much! Mark On Wed, Jan 18, 2012 at 10:53 AM, Matt Pouttu-Clarke matt.pouttu-cla...@icrossing.com wrote: I would strongly suggest using this method to read S3 only. I have had problems with writing large volumes of data to S3 from Hadoop using native

RE: How to find out whether a node is Overloaded from Cpu utilization ?

2012-01-18 Thread Bill Brune
Hi, Memory loading in most linux distro's is not readily available from top or the usual suspects, in fact looking at top is rather misleading. Linux can run just fine with committed memory greater than 100%, what you want to look at is the % of committed memory relative to the total memery.

I am trying to run a large job and it is consistently failing with timeout - nothing happens for 600 sec

2012-01-18 Thread Steve Lewis
The map tasks fail timing out after 600 sec. I am processing one 9 GB file with 16,000,000 records. Each record (think is it as a line) generates hundreds of key value pairs. The job is unusual in that the output of the mapper in terms of records or bytes orders of magnitude larger than the

Re: I am trying to run a large job and it is consistently failing with timeout - nothing happens for 600 sec

2012-01-18 Thread Tom Melendez
Sounds like mapred.task.timeout? The default is 10 minutes. http://hadoop.apache.org/common/docs/current/mapred-default.html Thanks, Tom On Wed, Jan 18, 2012 at 2:05 PM, Steve Lewis lordjoe2...@gmail.com wrote: The map tasks fail timing out after 600 sec. I am processing one 9 GB file with

Re: I am trying to run a large job and it is consistently failing with timeout - nothing happens for 600 sec

2012-01-18 Thread Alex Kozlov
Does it always fail at the same place? Does the task log shows something unusual? On Wed, Jan 18, 2012 at 3:46 PM, Steve Lewis lordjoe2...@gmail.com wrote: I KNOW is is a task timeout - what I do NOT know is WHY merely cutting the number of writes causes it to go away. It seems to imply that

Re: I am trying to run a large job and it is consistently failing with timeout - nothing happens for 600 sec

2012-01-18 Thread Steve Lewis
It always fails with a task timeout and that error gives me very little indication of where the error occurs. The one piece of data I have is that if I only call context.write 1 in 100 times it does not time out suggesting that it is not MY code that is timing out. I could try to time the write

Re: I am trying to run a large job and it is consistently failing with timeout - nothing happens for 600 sec

2012-01-18 Thread Leonardo Urbina
Perhaps you are not reporting progress throughout your task. If you happen to run a job large enough job you hit the the default timeout mapred.task.timeout (that defaults to 10 min). Perhaps you should consider reporting progress in your mapper/reducer by calling progress() on the Reporter

Re: I am trying to run a large job and it is consistently failing with timeout - nothing happens for 600 sec

2012-01-18 Thread Steve Lewis
1) I do a lot of progress reporting 2) Why would the job succeed when the only change in the code is if(NumberWrites++ % 100 == 0) context.write(key,value); comment out the test allowing full writes and the job fails Since every write is a report I assume that something in the

Re: I am trying to run a large job and it is consistently failing with timeout - nothing happens for 600 sec

2012-01-18 Thread Raj V
Steve Does the timeout happen for all the map jobs? Are you using some kind of shared storage for map outputs? Any problems with the physical disks? If the shuffle phase has started could the disks be I/O waiting between the read and write? Raj From: Steve

Re: I am trying to run a large job and it is consistently failing with timeout - nothing happens for 600 sec

2012-01-18 Thread Steve Lewis
In my hands the problem occurs in all map jobs - an associate with a different cluster - mine has 8 nodes - his 40 reports 80% of map tasks fail with a few succeeding - I suspect some kind of an I/O waiot but fail to see how it gets to 600sec On Wed, Jan 18, 2012 at 4:50 PM, Raj V

Re: I am trying to run a large job and it is consistently failing with timeout - nothing happens for 600 sec

2012-01-18 Thread Michael Segel
But Steve, it is your code... :-) Here is a simple test... Set your code up where the run fails... Add a simple timer to see how long you spend in the Mapper.map() method. only print out the time if its greater than lets say 500 seconds... The other thing is to update a dynamic counter in

Re: I am trying to run a large job and it is consistently failing with timeout - nothing happens for 600 sec

2012-01-18 Thread Raj Vishwanthan
You can try the following - make it into a map only job (for debug  purposes) - start your shuffle phase after all the maps are complete( there is a parameter for this) -characterize your disks for performance Raj  Sent from Samsung Mobile Steve Lewis lordjoe2...@gmail.com wrote: In my hands

Re: Best practices to recover from Corrupt Namenode

2012-01-18 Thread praveenesh kumar
Hi everyone, Any ideas on how to tackle this kind of situation. Thanks, Praveenesh On Tue, Jan 17, 2012 at 1:02 PM, praveenesh kumar praveen...@gmail.comwrote: I have a replication factor of 2, because of the reason that I can not afford 3 replicas on my cluster. fsck output was saying block