I spoke to Dario today about investigating uses for our Hadoop cluster.  This is an internal cluster but it's mirrored on labs so I'm posting to the public list in case people are interested in the technology and hearing what we're up to.

The questions we need to answer are :

• What's an easy way to import lots of data from MySQL without killing the source servers?  We've used sqoop and drdee's sqoopy but these would hammer the prod servers too hard we think.
• drdee mentioned a way to pass a comment with select statements to make them lower priority, is this documented somewhere?
• Could we just stand up the MySQL backups and import them?
• Could we import from the xml dumps?
• Is there a way to do incremental importing once an initial load is done?

Once we figure this out, the fun starts.  What are some useful questions once we have access to the core mediawiki db tables across all projects?