[EMAIL PROTECTED] wrote:
My error was that I intended to run nutch0 as job.tracker, but not as a datanode. So, when I ran bin/start-all.sh to start the cluster, it seemed to replicate the non-existent filesystem on nutch0; thereby starting to delete all my precious data.
It would be nice if this were harder to do. A simple solution I proposed would be to make it so that a new filesystem is not created automatically when a namenode is started in an empty directory. Rather a 'format' command could be required. A more complex solution might be to have a filesystem id. For example, some bits from each block id issued could be the filesystem id. When datanodes report blocks from a different filesystem, the namenode would ignore them rather than delete them.
Doug
