Re: Unknown Host Exception

Hi Steve, Can you suggest something on this error?? Regards Siddharth On Mon, Oct 11, 2010 at 3:05 PM, Steve Loughran wrote: > On 10/10/10 16:07, siddharth raghuvanshi wrote: > >> Hi, >> >> Thanks for your reply.. >> >> In browser, >> >> http://localhost:50030/jobtracker.jsp is opening

how many times has a file been read?

Hi, guys, Is there any way to know how many times the files in the HDFS have been read? And read by who, when? And also some other details like how much time spent to read a file?Thanks Dennis

Re: Why hadoop is written in java?

The Java memory overhead is a quite serious problem, and a legitimate and serious criticism of Hadoop. For MapReduce applications, it is often (although not always) possible to improve performance by doing more work in memory (e.g., using combiners and the like) before emitting data. Thus, the more

Re: Why hadoop is written in java?

I agree with others in this list that Java provides faster software development, the IO cost in Java is practically the same as in C/C++, etc. In short, most pieces of distributed software can be written in Java without any performance hiccups, as long as it is only system metadata that is handled

Re: Why hadoop is written in java?

Check out this thread: https://www.quora.com/Why-was-Hadoop-written-in-Java -- View this message in context: http://lucene.472066.n3.nabble.com/Why-hadoop-is-written-in-java-tp1673148p1684291.html Sent from the Hadoop lucene-users mailing list archive at Nabble.com.

Finding replicants of an HDFS file

Is there a command that will display which nodes the blocks of a file are replicated to? We're prototyping a hadoop cluster and want to perform some failure testing where we kill the correct combination of nodes to make a file inaccessible, however I haven't been able to track down a command that

Finding replicants of an HDFS file

Is there a command that will display which nodes the blocks of a file are replicated to? We're prototyping a hadoop cluster and want to perform some failure testing where we kill the correct combination of nodes to make a file inaccessible, however I haven't been able to track down a command that

Re: increase BytesPerChecksum decrease write performance??

This might be caused by the default wirte packet size. In HDFS, user data are pipeline to datanodes in packets. The default packet size is 64K. If the chunksize is bigger than 64K, the packet size automatically adjusts to include at least one chunk. Please set the packet size to be 8MB by configur

Re: Unknown Host Exception

Check your etc/hosts file. I usually resolve this issue by fixing some weirdness or misconfiguration in that file. Regards Steve Watt From: Steve Loughran To: common-user@hadoop.apache.org Date: 10/11/2010 04:36 AM Subject: Re: Unknown Host Exception On 10/10/10 16:07, siddharth raghuvans

load a serialized object in hadoop

Hi, I want to load a serialized HashMap object in hadoop. The file of stored object is 200M. I could read that object efficiently in JAVA by setting -Xmx as 1000M. However, in hadoop I could never load it into memory. The code is very simple (just read the ObjectInputStream) and there is yet

Upgrade hadoop hive metastore

Im trying to upgrade from hadoop .18 to .20 as well as upgrade hive from .4 to .5 and switch the metastore from derby to mysql. The hadoop upgrade went smoothly but when i try and connect to it with hive via the .4 version on derby i get the following: java.sql.SQLSyntaxErrorException: Table/V

Re: Why hadoop is written in java?

On 11/10/10 16:56, Konstantin Boudnik wrote: > To second your point ;-) Reminds me of times when Sun Micro bought GridEngine > (C-app). Me and a couple other folks were developing Distributed Task > execution > Framework (written in Java on top of JINI). > > Every time new version of eh... Window

Re: Why hadoop is written in java?

To second your point ;-) Reminds me of times when Sun Micro bought GridEngine (C-app). Me and a couple other folks were developing Distributed Task execution Framework (written in Java on top of JINI). Every time new version of eh... Windows was coming around the corner Grid people were screaming

Re: how to set diffent VM parameters for mappers and reducers?

On 11/10/10 11:13, Vitaliy Semochkin wrote: > I guess we should create a feature request ) no, If it doesn't work it is a bug. Therefore you should -get the latest released version of the code, that is 0.21 -search for the string there, check they are both actually being used, see what happens t

Re: how to set diffent VM parameters for mappers and reducers?

I guess we should create a feature request ) On Mon, Oct 11, 2010 at 7:34 AM, Medha Atre wrote: > I too need a solution for this as I am facing same problem. > > Thanks in anticipation. > > > On Thu, Oct 7, 2010 at 3:50 PM, Vitaliy Semochkin > wrote: >> Hi, >> >> I tried using  mapred.map.chil

Re: Unknown Host Exception

On 10/10/10 16:07, siddharth raghuvanshi wrote: Hi, Thanks for your reply.. In browser, http://localhost:50030/jobtracker.jsp is opening fine but http://localhost:50060/ is not. Since jobtracker is running, so I'm assuming localhost is reachable.. am I wrong?? I'd worry more

[UI] HTTP ERROR: 410 Failed to retrieve syslog log for task: attempt*

Hi, I met the error "HTTP ERROR: 410", when look up the log of attempt from the UI part "Task Logs". HTTP ERROR: 410Failed to retrieve syslog log for task: attempt_201009090239_0693_m_01_0 RequestURI=/tasklog Powered by Jetty:// Version: Hadoop 0.20.2 Task AttemptsMachineStatusProgr