60 real HDFS questions from the Big Data bank, as asked in Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd — free to start.
1. What is HDFS default block size?
Junior
A.the architecture using multiple independent NameNodes, each managing a namespace volume, to scale metadata beyond a single NameNode's capacity
B.128 MB
C.a client-side mount table that presents multiple federated HDFS namespaces as a single unified file system view
D.too many files exhausting NameNode memory (~150 bytes each)
B.HDFS default block size — the HDFS process where a standby or secondary NameNode merges the edit log into the fsimage to bound recovery time
C.HDFS default block size — an HDFS daemon that stores the shared edit log so the standby NameNode stays in sync with the active one
D.HDFS default block size — an HDFS setup with active and standby NameNodes sharing edits via a JournalNode quorum to remove the single point of failure
A.the HDFS setup running active and standby NameNodes sharing edits through a JournalNode quorum to remove the single point of failure
B.the HDFS process where a standby or secondary NameNode merges the edit log into the fsimage to bound recovery time
C.3
D.the HDFS storage policy that protects data with parity blocks instead of full replicas, cutting storage overhead from 200 percent to about 50 percent
A.HDFS default replication factor — an HDFS daemon that stores the shared edit log so the standby NameNode stays in sync with the active one
B.HDFS default replication factor — the fixed-size unit, 128 MB by default, into which HDFS splits files for distributed storage and replication
C.HDFS default replication factor — the HDFS setup running active and standby NameNodes sharing edits through a JournalNode quorum to remove the single point of failure
A.NameNode — the HDFS storage policy that protects data with parity blocks instead of full replicas, cutting storage overhead from 200 percent to about 50 percent
B.NameNode — the HDFS policy that places block replicas across racks to balance fault tolerance against cross-rack bandwidth
C.NameNode — a feature reducing the 3x replication storage overhead
D.NameNode — the HDFS service storing filesystem metadata in memory
A.small-files problem — too many files exhausting NameNode memory (~150 bytes each)
B.small-files problem — the architecture using multiple independent NameNodes, each managing a namespace volume, to scale metadata beyond a single NameNode's capacity
C.small-files problem — the HDFS optimization letting a client on the same node read block files directly from local disk, bypassing the DataNode process
D.small-files problem — an architecture using multiple independent NameNodes, each managing a namespace volume, to scale metadata beyond one NameNode
A.the HDFS policy that places block replicas across racks to balance fault tolerance against cross-rack bandwidth
B.a feature reducing the 3x replication storage overhead
C.the HDFS storage policy that protects data with parity blocks instead of full replicas, cutting storage overhead from 200 percent to about 50 percent
A.Hadoop 3 erasure coding — a feature reducing the 3x replication storage overhead
B.Hadoop 3 erasure coding — a client-side mount table that presents multiple federated HDFS namespaces as a single unified file system view
C.Hadoop 3 erasure coding — the HDFS tool that redistributes blocks across DataNodes to even out disk utilization after nodes are added or fill unevenly
D.Hadoop 3 erasure coding — an HDFS daemon that stores the shared edit log so the standby NameNode stays in sync with the active one
B.Block — the fixed-size unit, 128 MB by default, into which HDFS splits files for distributed storage and replication
C.Block — the HDFS storage policy that protects data with parity blocks instead of full replicas, cutting storage overhead from 200 percent to about 50 percent
D.Block — an HDFS daemon that stores the shared edit log so the standby NameNode stays in sync with the active one
B.NameNode high availability — the HDFS service storing filesystem metadata in memory
C.NameNode high availability — an HDFS daemon that stores the shared edit log so the standby NameNode stays in sync with the active one
D.NameNode high availability — an HDFS setup with active and standby NameNodes sharing edits via a JournalNode quorum to remove the single point of failure
Showing 30 of 60 HDFS questions — the full set, with answers, explanations and an AI tutor on every question, is inside.
Free to start
Answers, AI explanations, and a scored voice mock interview
Sign up free to check your answers with explanations, ask the AI tutor anything on any question, and take one full AI mock interview — scored like a real panel.