Book Image

MongoDB Administrator???s Guide

By : Cyrus Dasadia
Book Image

MongoDB Administrator???s Guide

By: Cyrus Dasadia

Overview of this book

MongoDB is a high-performance and feature-rich NoSQL database that forms the backbone of the systems that power many different organizations. Packed with many features that have become essential for many different types of software professional and incredibly easy to use, this cookbook contains more than 100 recipes to address the everyday challenges of working with MongoDB. Starting with database configuration, you will understand the indexing aspects of MongoDB. The book also includes practical recipes on how you can optimize your database query performance, perform diagnostics, and query debugging. You will also learn how to implement the core administration tasks required for high-availability and scalability, achieved through replica sets and sharding, respectively. You will also implement server security concepts such as authentication, user management, role-based access models, and TLS configuration. You will also learn how to back up and recover your database efficiently and monitor server performance. By the end of this book, you will have all the information you need—along with tips, tricks, and best practices—to implement a high-performance MongoDB solution.
Table of Contents (17 chapters)
Title Page
Credits
About the Author
About the Reviewers
www.PacktPub.com
Customer Feedback
Preface

Checking replication lag of nodes in a replica set


The most ideal state for a replica set is when all nodes within the cluster are in sync. In this recipe, we will look at how to check the replication lag of nodes in a replica set.

Getting ready

We will need at least a multinode replica set cluster. You can refer to the Adding a node in a replica set recipe in Chapter 4High Availability with Replication, for more details.

How to do it...

  1. Ensure all nodes are up and connect to the primary node of the replica set using mongo shell.
  2. Fetch the current replication information:
rs.printReplicationInfo()
  1. You should see output similar to this:
configured oplog size: 1578.62548828125MB
log length start to end: 142363secs (39.55hrs)
oplog first event time: Sun Oct 08 2017 18:54:12 GMT+0530 (IST)
oplog last event time: Tue Oct 10 2017 10:26:55 GMT+0530 (IST)
now: Tue Oct 10 2017 10:26:59 GMT+0530 (IST)
  1. Check the current replication information:
rs.printSlaveReplicationInfo()
  1. You should see output similar to...