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From Amit Kabra <amitkabrai...@gmail.com>
Subject Journal nodes , QJM requirement
Date Mon, 27 Feb 2017 04:59:06 GMT
Hi Hadoop Users,

I have one question, didn't get information on internet.

Why hadoop needs journaling system. In order to sync Active / Standby NN,
instead of using Journal node or any shared system, can't it do
master-slave or multi master replication where for any write master will
write to other master/slave as well and only once replication is done at
other sites will commit / accept the write ?

One reason I could think is journal node writes data from NN in append only
mode which *might* make it faster as compared to writing to slave / another
master for replication but I am not sure.

Any pointers ?

Amit Kabra.

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