Six areas to improve Hadoop availability when dealing with common scenarios like host maintenance, configuration changes, software upgrades, host failures:
A number of efforts are under way to improve Hadoop availability, and implement missing functionality required by the above use cases. Tasks related to HDFS availability are tracked here, tasks related to MapReduce availability are tracked here.
Hadoop community is already working to improve Hadoop availability and these features will be available sooner than seeing Yahoo’s next generation of Hadoop MapReduce.
Original title and link: Improvements to Hadoop Availability (NoSQL databases © myNoSQL)