Shulou(Shulou.com)05/31 Report--

This article introduces Hadoop2.x how to solve the NN single point failure problem, the content is very detailed, interested friends can refer to, hope to be helpful to you.

Hadoop solves the problem of single point of failure mainly in two ways:

1. NFS file sharing

2. Proposed by CLOUDERA in QJM mode.

There are two nn in Hadoop2.x, one is active namenode state is active, the other is standy namenode state is standy, both are switched, but there is one and only one active!

Nfs is a heavyweight that needs to be deployed and maintained separately. As a storage for data sharing between namenode and standy namenode, the disadvantage is that if active, then node or standy namenode has a network failure with nfs, it will cause data synchronization problems.

QJM solves the problems faced by nfs. Data is shared between active namenode and standy namenode through a set of journalnode odd numbers. Active nn writes the latest edits files to 2n+1. Only 1 journalnode writes successfully, and then standy nn starts to read. This way supports fault tolerance!

About Hadoop2.x how to solve the NN single point failure problem is shared here, I hope the above content can be of some help to you, can learn more knowledge. If you think the article is good, you can share it for more people to see.

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