Apache HBase is a rapidly-evolving random-access distributed data store built on top of Apache Hadoop's HDFS and Apache ZooKeeper. Drawing from real-world support experiences, this talk provides administrators insight into improving HBase's availability and recovering from situations where HBase is not available. We share tips on the common root causes of unavailability, explain how to diagnose them, and prescribe measures for ensuring maximum availability of an HBase cluster. We discuss new features that improve recovery time such as distributed log splitting as well as supportability improvements. We will also describe utilities including new failure recovery tools that we have developed and contributed that can be used to diagnose and repair rare corruption problems on live HBase systems.