Database to use with Hadoop

[Mark Kerzner-2]

Hi,
I run Elastic MapReduce. The output of my application is a text file, where
each line is essentially a set of fields. It will fit very nicely into a
simple database, but which database

   1. Is persistent after cluster shutdown;
   2. Can be written to by many reducers?

Amazon SimpleDB could do - but does it work with Hadoop?

Thank you,
Mark