A must-know for anyone looking for agile Hadoop admin advanced interview questions, this is one of the frequent questions asked of senior Hadoop admin developers as well. Fault-tolerance of a system is a smart specialized ability that prevents any kind of potential disruption or failure to the nodes and ensures business continuity and high availability using backup nodes that replaces the failed ones. The different types of fault-tolerant systems can be the following:  Transient, Spasmodic or Permanent hardware faults.  Software and Hardware design errors.  Human-induced errors or physical damage.  In a faulty system both recovery time (RTO) and data loss (RPO) are zero. In order to maintain fault tolerance at all times, organizations must possess redundant inventory of formatted computing devices and a secondary uninterruptible power supply. The objective is to prevent mission-critical applications and networks from failing, with a focus on uptime and downtime issues.