No, I am using 0.21.0 for better performance. I am interested in DistributedCache so certain libraries can be found during MR processing. As it is now, I'm getting ClassNotFoundException being thrown by the Reducers. The Driver throws no error, the Reducer(s) does. It would seem something is not being distributed across the cluster as I assumed it would. After all, the whole business is in a single, executable jar file.
On 2 March 2012 09:46, Kunaal <kunaalbha...@gmail.com> wrote: > Are you looking to use DistributedCache for better performance? > > On Fri, Mar 2, 2012 at 9:42 AM, Geoffry Roberts > <geoffry.robe...@gmail.com>wrote: > > > This is a tardy response. I'm spread pretty thinly right now. > > > > DistributedCache< > > > http://hadoop.apache.org/common/docs/r1.0.0/mapred_tutorial.html#DistributedCache > > >is > > apparently deprecated. Is there a replacement? I didn't see anything > > about this in the documentation, but then I am still using 0.21.0. I have > > to for performance reasons. 1.0.1 is too slow and the client won't have > > it. > > > > Also, the DistributedCache< > > > http://hadoop.apache.org/common/docs/r1.0.0/mapred_tutorial.html#DistributedCache > > >approach > > seems only to work from within a hadoop job. i.e. From within a > > Mapper or a Reducer, but not from within a Driver. I have libraries > that I > > must access both from both places. I take it that I am stuck keeping two > > copies of these libraries in synch--Correct? It's either that, or copy > > them into hdfs, replacing them all at the beginning of each job run. > > > > Looking for best practices. > > > > Thanks > > > > On 28 February 2012 10:17, Owen O'Malley <omal...@apache.org> wrote: > > > > > On Tue, Feb 28, 2012 at 5:15 PM, Geoffry Roberts > > > <geoffry.robe...@gmail.com> wrote: > > > > > > > If I create an executable jar file that contains all dependencies > > > required > > > > by the MR job do all said dependencies get distributed to all nodes? > > > > > > You can make a single jar and that will be distributed to all of the > > > machines that run the task, but it is better in most cases to use the > > > distributed cache. > > > > > > See > > > > > > http://hadoop.apache.org/common/docs/r1.0.0/mapred_tutorial.html#DistributedCache > > > > > > > If I specify but one reducer, which node in the cluster will the > > reducer > > > > run on? > > > > > > The scheduling is done by the JobTracker and it isn't possible to > > > control the location of the reducers. > > > > > > -- Owen > > > > > > > > > > > -- > > Geoffry Roberts > > > > > > -- > "What we are is the universe's gift to us. > What we become is our gift to the universe." > -- Geoffry Roberts
