Sequence File usage queries

Hi, I have a use case to upload some tera-bytes of text files as sequences files on HDFS. These text files have several layouts ranging from 32 to 62 columns (metadata). What would be a good way to upload these files along with their metadata: i) creating a key, value class per text file layout

When use hadoop mapreduce?

Hi, I like to know, depending on my problem, when should I use or not use Hadoop MapReduce? Does exist any list that advices me to use or not to use MapReduce? Thanks, -- Pedro