Hi, I want to test how Hadoop and HBase are performing. I have a cluster with 1 namenode and 4 datanodes. I use Hadoop 0.19.1 and HBase 0.19.2.
I first ran a few tests when the 4 datanodes use local storage specified in dfs.data.dir. Now, I want to see what is the tradeoff if I switch from local storage to network mounted storage (I know it sounds like a crazy idea but unfortunately I have to explore this possibility). I would like to be able to change the dfs.data.dir and maybe in two steps be able to switch to the network mounted storage. What I had in mind was the following steps : 0. Assume initial status is a working cluster with local storage, e.g. dfs.data.dir set to local_storage_path. 1. Stop cluster: bin/stop-dfs 2. Change dfs.data.dir by adding the network_storage_path to the local storage_path. 3. Start cluster: bin/start-dfs (this will format the new network locations, which is nice) 4. <Perform some sort of directed balancing of all the data towards the network storage location> 5. Stop cluster: bin/stop-dfs 6. Change dfs.data.dir parameter to only contain local_storage_path 7. Start cluster and live happily ever after :-). The problem is , I don;t know if there is a command or an option to achieve step 4. Do you have any suggestions ? I found some info on how to add datanodes, but there is not much info on how to remove safely (without losing data etc) datanodes or storage locations on a particular node. Is this possible? Many thanks, Alexandra. -- View this message in context: http://www.nabble.com/How-to-replace-the-storage-on-a-datanode-without-formatting-the-namenode--tp23542127p23542127.html Sent from the Hadoop core-user mailing list archive at Nabble.com.
