How does Hadoop's block replacement policy work?

0 votes
I'm working on a Hadoop cluster and my cluster has nodes in seven racks, and I have provided a rack topology script. What is Hadoop's block placement policy, assuming a block replication factor of three?
Aug 16, 2018 in Big Data Hadoop by Meci Matt
• 9,400 points
47 views

1 answer to this question.

0 votes
In your case, One copy of the block is written to a node in one rack; two copies are written to two nodes in a different rack.
Actually, what happens is HDFS uses rack-aware replica placement policy. In default configuration there are total 3 copies of a datablock on HDFS, 2 copies are stored on datanodes on same rack and 3rd copy on a different rack.

Hope this helps!
answered Aug 16, 2018 by nitinrawat895
• 10,030 points

Related Questions In Big Data Hadoop

0 votes
1 answer

How does the HDFS Client knows the block size while writing?

HDFS is designed in a way where ...READ MORE

answered Mar 27, 2018 in Big Data Hadoop by kurt_cobain
• 9,240 points
25 views
0 votes
1 answer

How does Avro schema evolution work?

If you have one avro file and ...READ MORE

answered Sep 19, 2018 in Big Data Hadoop by Frankie
• 9,810 points
117 views
0 votes
1 answer
0 votes
1 answer

How to work with distributed cache in Hadoop?

The problem with your code is that ...READ MORE

answered Apr 20, 2018 in Big Data Hadoop by kurt_cobain
• 9,240 points
348 views
0 votes
1 answer

Hadoop dfs -ls command?

In your case there is no difference ...READ MORE

answered Mar 16, 2018 in Big Data Hadoop by kurt_cobain
• 9,240 points
753 views
0 votes
1 answer

Hadoop Mapreduce word count Program

Firstly you need to understand the concept ...READ MORE

answered Mar 16, 2018 in Data Analytics by nitinrawat895
• 10,030 points
2,027 views
0 votes
1 answer

How to get started with Hadoop?

Well, hadoop is actually a framework that ...READ MORE

answered Mar 21, 2018 in Big Data Hadoop by coldcode
• 2,010 points
60 views
0 votes
10 answers

hadoop fs -put command?

copy command can be used to copy files ...READ MORE

answered Dec 7, 2018 in Big Data Hadoop by Sujay
10,262 views
0 votes
1 answer

How to analyze block placement on datanodes and rebalancing data across Hadoop nodes?

HDFS provides a tool for administrators i.e. ...READ MORE

answered Jun 21, 2018 in Big Data Hadoop by nitinrawat895
• 10,030 points
91 views
0 votes
1 answer

How does HDFS Federation help HDFS Scale horizontally?

Let me try to explain you the ...READ MORE

answered Jul 12, 2018 in Big Data Hadoop by nitinrawat895
• 10,030 points
153 views