You configure you cluster with HDFS High Availability (HA) using Quorum-Based storage. You do not implement HDFS Federation. What is the maximum number of NameNodes daemon you should run on you…

Question

Options

• AUnlimited. HDFS High Availability (HA) is designed to overcome limitations on the number of NameNodes
• BTwo active NameNodes and one Standby NameNode
• COne active NameNode and one Standby NameNode
• DTwo active NameNodes and two Standby NameNodes

• A
  18% (6)
• B
  3% (1)
• C
  70% (23)
• D
  9% (3)

Explanation

In a typical HA cluster, two separate machines are configured as NameNodes. At any point in time, one of the NameNodes is in an Active state, and the other is in a Standby state. The Active NameNode is responsible for all client operations in the cluster, while the Standby is simply acting as a slave, maintaining enough state to provide a fast failover if necessary. Note: It is vital for the correct operation of an HA cluster that only one of the NameNodes be active at a time. Otherwise, the namespace state would quickly diverge between the two, risking data loss or other incorrect results. In order to ensure this property and prevent the so-called "split-brain scenario," the JournalNodes will only ever allow a single NameNode to be a writer at a time. During a failover, the NameNode which is to become active will simply take over the role of writing to the JournalNodes, which will effectively prevent the other NameNode from continuing in the Active state, allowing the new Active NameNode to safely proceed with failover.

No community discussion yet for this question.