Hi All,
I have one very basic query regarding the replication factor in HDFS.
Scenario:
I have 4 node cluster : 3 data nodes and 1 master node.
The replication factor is 3. So ideally each data node would get one
replica .
Assume that meanwhile one of the data node went down.
so ideally we
Your write will not succeed. You will get an exception like could
only be replicated to 0 nodes, instead of 1
More details here:
http://www.bigdataplanet.info/2013/10/Hadoop-Tutorial-Part-4-Write-Operations-in-HDFS.html
1. *How hadoop will take care of balancing of replicas as the required
replicas are 3 , but we have only 2 data nodes up and running.*
*Ans:* As here the replication factor is three. The data block will be
replicated three time within 2 nodes. Block replication is random.
*2. What happens when
You will get under replicated block and missing replicas when you run hdfs
fsck /
you may see info like the following
Under replicated blk_-4791859336845413240_1544. Target Replicas
is 3 but found 2 replica(s).
On Fri, Sep 19, 2014 at 5:36 AM, adarsh deshratnam
adarsh.deshrat...@gmail.com
Interesting. I thought that the write would fail in case if # of nodes
downs is greater than min-replication property. So in reality we only get a
warning while writing (and a info message through fsck.)
Regards,
Shahab
On Fri, Sep 19, 2014 at 9:26 AM, Abirami V abiramipand...@gmail.com wrote:
