AFAIK, it might not be possible with a single namenode. You could look into federated namenodes - but I do not think even federated NN would allow that today (I might be wrong though).
If you have two different NNs, why would you need separate libs etc? You could point to the respective namenode while accessing that namenode. -John George On 10/6/11 4:19 AM, "Vincent Boucher" <vin.bouc...@gmail.com> wrote: >Hello, > >We are wondering if it is possible to require that the namenode redirects >the >blocks of the files of a given directory to a particular set of datanodes? > >Our case is the following: > > - Servers > 10 x mass storage servers of each 50TB, RAID6 > -> 500TB available for hdfs > 30 x working nodes with 6TB (no RAID) > -> 180TB available for hdfs > >We'd like that the files stored in > /hdfs/ms >be hosted on the mass storage (ms) servers, >while the files in > /hdfs/wn >be hosted on the working nodes (wn). > >Having 2 namenodes, one for each subdir /hdfs/ms or /hdfs/wn would do the >job. >However, at the client level it means dealing with to hadoop >installation/libs ... not great. > >It is possible to do it with a single namenode? > >Cheers, > >Vincent
