I want to upgrade a 1TB cluster from hadoop 0.20.3 to hadoop 1.0.3.
I am interested to know how long does the hdfs upgrade take and in general
how long it takes from deploying new versions until the cluster is back to
running heavy MapReduce ?
I'd also appreciate it if someone could elaborate about how the hdfs file
system is actually executed - I read in the book tat data is not replicated
but the DNs use hard links.