MongoDB is a non-relations database and well known in the latest trends for storing data in json form. This slide will help you to understand the advanced concept of MongoDB with the help of sharding. This slide will cover: Architecture of sharded cluster. Query handling in sharded cluster. Data Distribution Method. Replica Sets.

1. MongoDB Clusters
Shredded Databases
Presenter: Abhinav Jha
(Software Developer - TMotions Global Pvt. Ltd.)

2. MongoDB (Journey till now)
● Setting up MongoDB environment.
● Creating Databases, Collections and Documents.
● Document Schema using NF3.
● Creating Queries for manipulating data with Robo 3T.

3. Latest News
● Latest version: Mongo 4.0
○ https://docs.mongodb.com/manual/release-notes/4.0/
● For further news and cool stuffs for mongo
○ https://www.mongodb.com/news

4. What we will learn today?
● Architecture of sharded cluster.
● Query handling in sharded cluster.
● Data Distribution Method.
● Replica Sets.

5. What is Replication
Replication is a concept
of keeping multiple
copies of your data.
We need replication
because you can never
assume that all of the
servers are always
available.

6. Standalone Vs Replicated Solution
Standalone writes data to a
single server.
Replicated Solution we keep
copies of data into different
servers.

7. How it works.
● Binary Replications - strict consistencies along all the
servers since it is based on memory index.
● Statement Based Replications - not bound by operating
systems or any machine level dependencies.

8. Setting up replica set
Create a config file with the storage, server, port and replica set name.

9. Connect to Node1:

10. Important Queries
rs.initiate()
rs.status()
rs.add("<host-name>:<port-number>")
rs.isMaster()
rs.stepDown()
rs.remove("<host-name>:<port-number>")

11. Arbitrary Node (Only for election)
rs.addArb("m103.mongodb.university:28000")

12. Hidden Node (Stores Backups)
cfg = rs.conf()
cfg.members[3].votes = 0
cfg.members[3].hidden = true
cfg.members[3].priority = 0
rs.reconfig(cfg)

13. Sharding
If the data grows to the limit
that our server can't handle
the data.
We use Sharding

14. Vertical Sharding
● Add more RAM, Disk Space or processors.
● Very Expensive
● Cloud base does not allow Vertical scaling

15. Horizontal Scaling
● MongoDB allows horizontal
scaling.
● Add more machines.
● Distribute the data set across
the machines

16. Sharded Clusters

17. Mongos

20. Setup Shard
sharding:
clusterRole: configsvr
replication:
replSetName: aj-replicaset
net:
bindIp: localhost
port: 26001
storage:
dbPath: /var/mongodb/db/csrs1

21. Running mongo instances
mongod -f csrs_1.conf
mongod -f csrs_2.conf
mongod -f csrs_3.conf
Connect one of the Server
mongo --port 26001

22. Setup Replica Set
rs.initiate()
rs.add("192.168.103.100:26002")
rs.add("192.168.103.100:26003")

23. Mongos.cfg
sharding:
configDB: aj-replicaset/localhost:26001,localhost:26002,localhost:26003
net:
bindIp: localhost
port: 26000
processManagement:
fork: true
sh.status()
sh.addShard("m103-repl/192.168.103.100:27012")

24. Update Node Configs
sharding:
clusterRole: shardsvr
storage:
dbPath: /var/mongodb/db/node1
wiredTiger:
engineConfig:
cacheSizeGB: .1
net:
bindIp: 192.168.103.100,localhost
port: 27011
replication:
replSetName: aj-replicaset

25. References
https://docs.mongodb.com/manual/core/sharded-cluster-
components/
https://docs.mongodb.com/manual/tutorial/atlas-free-tier-
setup/
https://docs.mongodb.com/manual/crud/
https://docs.mongodb.com/manual/replication/

26. Thanks For Your Time
Any Query Please Let Me Know:
abhinav.jha@tmotions.com
abhinav.jha@haymarket.com