In context to the scaling of the MongoDB
MongoDB
MongoDB is a cross-platform document-oriented database program. Classified as a NoSQL database program, MongoDB uses JSON-like documents with schema. MongoDB is developed by MongoDB Inc. and licensed under the Server Side Public License.
How to take backup from MongoDB and restore to MongoDB?
Use the following command to backing up: $ mongodump --out /tmp/backup_v2. After successful backup, let’s move to the database directory and see what it has. It has BSON and JSON collections without compression. $ ls -la /tmp/backup_v2/db1. Now restore data from this backup using the following command:
How to configure MongoDB replication?
Step by Step MongoDB Replication setup on Windows
- Start standalone server as shown below. mongod --dbpath "C:\Program Files\MongoDB\Server\4.0\data" --logpath "C:\Program Files\MongoDB\Server\4.0\log\mongod.log" --port 27017 --storageEngine=wiredTiger --journal --replSet r2schools
- Connect to the server with port number 27017 mongo --port 27017
- Then, create variable rsconf. ...
Is MongoDB better than PostgreSQL?
Write speed: PostgreSQL is magically faster than MongoDB if documents are stored in a tabular format but that’s not the case with MongoDB because documents are stored in JSON format. When data in...
How to create a sharded cluster in MongoDB?
The procedure is as follows:
- Create the initial three-member replica set and insert data into a collection. See Set Up Initial Replica Set.
- Start the config servers and a mongos. See Deploy Config Server Replica Set and mongos.
- Add the initial replica set as a shard. See Add Initial Replica Set as a Shard.
- Create a second shard and add to the cluster. ...
- Shard the desired collection. ...
What is sharding and replication in Nosql?
— Sharding distributes different data across multiple servers. — each server acts as the single source for a subset of data. — Replication copies data across multiple servers. — each bit of data can be found in multiple places. — A system may use either or both techniques.
What is MongoDB Sharding?
Advertisements. Sharding is the process of storing data records across multiple machines and it is MongoDB's approach to meeting the demands of data growth. As the size of the data increases, a single machine may not be sufficient to store the data nor provide an acceptable read and write throughput.
What is replication in MongoDB?
In simple terms, MongoDB replication is the process of creating a copy of the same data set in more than one MongoDB server. This can be achieved by using a Replica Set. A replica set is a group of MongoDB instances that maintain the same data set and pertain to any mongod process.
What is the difference between Replicaset and sharding in MongoDB?
Replication: A replica set in MongoDB is a group of mongod processes that maintain the same data set. Sharding: Sharding is a method for storing data across multiple machines.
Is sharding better than replication?
What is the difference between replication and sharding? Replication: The primary server node copies data onto secondary server nodes. This can help increase data availability and act as a backup, in case if the primary server fails. Sharding: Handles horizontal scaling across servers using a shard key.
Why is sharding used?
Sharding is a method for distributing a single dataset across multiple databases, which can then be stored on multiple machines. This allows for larger datasets to be split in smaller chunks and stored in multiple data nodes, increasing the total storage capacity of the system.
What is sharding in NoSQL?
Sharding is a partitioning pattern for the NoSQL age. It's a partitioning pattern that places each partition in potentially separate servers—potentially all over the world. This scale out works well for supporting people all over the world accessing different parts of the data set with performance.
Why do we need replication in MongoDB?
Replication provides redundancy and increases data availability with multiple copies of data on different database servers. Replication protects a database from the loss of a single server. Replication also allows you to recover from hardware failure and service interruptions.
What is crud in MongoDB?
The basic methods of interacting with a MongoDB server are called CRUD operations. CRUD stands for Create, Read, Update, and Delete. These CRUD methods are the primary ways you will manage the data in your databases.
Is sharding the same as partitioning?
Sharding and partitioning are both about breaking up a large data set into smaller subsets. The difference is that sharding implies the data is spread across multiple computers while partitioning does not. Partitioning is about grouping subsets of data within a single database instance.
What is Nosql data replication?
Replication: Replication copies data across multiple servers, so each bit of data can be found in multiple places. Replication comes in two forms, Master-slave replication makes one node the authoritative copy that handles writes while slaves synchronize with the master and may handle reads.
What is indexing MongoDB?
The index stores the value of a specific field or set of fields, ordered by the value of the field. The ordering of the index entries supports efficient equality matches and range-based query operations. In addition, MongoDB can return sorted results by using the ordering in the index.
Is sharding the same as partitioning?
Sharding and partitioning are both about breaking up a large data set into smaller subsets. The difference is that sharding implies the data is spread across multiple computers while partitioning does not. Partitioning is about grouping subsets of data within a single database instance.
What is meant by sharding?
Sharding is a type of database partitioning that separates large databases into smaller, faster, more easily managed parts. These smaller parts are called data shards. The word shard means "a small part of a whole."
What is sharding in NoSQL?
Sharding is a partitioning pattern for the NoSQL age. It's a partitioning pattern that places each partition in potentially separate servers—potentially all over the world. This scale out works well for supporting people all over the world accessing different parts of the data set with performance.
What does Sharded mean?
(ˈʃɑːdɪd) adj. reduced to shards or fragmentary pieces.
How does MongoDB use shard keys?
MongoDB uses the shard key to distribute the collection’s documents across shards by assigning a range of values to a shard. Shard keys are based on fields inside each document. The values in those fields will decide on which shard the document will reside, according to the shard ranges and amount of chunks.
What is a shard key in MongoDB?
MongoDB uses the shard key to distribute the collection’s documents across shards by assigning a range of values to a shard.
What is sharding in computing?
Sharding is a method for distributing data across multiple machines, enabling horizontal scaling (as op posed to vertical scaling). Vertical scaling refers to increasing the power of a single machine or single server through a more powerful CPU, increased RAM, or increased storage capacity. If physical limitations were not an issue, vertical scaling ...
How many processes can a Mongod server have?
Each config server replica set can have any number of mongod processes (up to 50), with the following exceptions: no arbiters and no zero-priority members. For each of those, you will need to start it with the --configsvr option. For example:
Is each shard a replica?
As mentioned before, each shard is a replica set in and of itself. This process will be similar to the config servers, but using the --shardsvr option. Make sure to use a different replica set name for each shard.
What is a sharding in MongoDB?
Sharding is MongoDB's solution for meeting the demands of data growth. Sharding stores data records across multiple servers to provide faster throughput on read and write queries, particularly for very large data sets.
What is sharding and replication?
Both replication and sharding are forms of horizontal scaling to create a high availability (HA) setup. Both replication and sharding can be used (individually or together) for horizontal scaling of a MongoDB installation.
What is MongoDB replication?
Replication is MongoDB's solution for providing stability, backup, and disaster recovery to a MongoDB installation. This process copies and synchronizes the replica data set across multiple servers. This prevents downtime if one server goes offline.
What is sharding in a server?
Sharding: Handles horizontal scaling across servers using a shard key. This means that rather than copying data holistically, sharding copies pieces of the data (or “shards”) across multiple replica sets.
How does sharding work?
With sharding, you’re sending pizza slices to several different replica sets. Combined together, you have access to the entire pizza pie. Replication and sharding can work together to form something called a sharded cluster, where each shard is replicated in turn to preserve the same high availability.
What port is Mongod listening to?
From the same machine where one of the mongod is running, start the mongo shell. To connect to the mongod listening to localhost on the default port of 27017 , simply issue:
Why is replication important?
Replication has several benefits. It increases data availability and reliability thanks to there being multiple live copies of your data. Replication is also helpful in case of an event like hardware failure or a server crash.
Is lag normal in replication?
Short windows of replication lag are normal, and should be considered in systems that choose to read the eventually-consistent secondary data. Replication lag can also prevent secondary servers from assuming the primary role if the primary goes down. If you want to check your current replication lag:
Can you use MongoDB Atlas?
Rather than having to configure and manage everything yourself, you can always use MongoDB Atlas. It streamlines and automates your replica sets, making the process effortless for you. MongoDB Atlas can also deploy globally sharded replica sets with few clicks, enabling data locality, disaster recovery, and multi-region deployments.
What is MongoDB database?
Introduction. MongoDB is a NoSQL, document-based and a general-purpose database built for modern applications. Being a document-based database, MongoDB stores data in JSON format which makes it more expressive than the traditional row/column model.
What is the role of a MongoDB router?
The routers are responsible for forwarding database operations to the correct shard.
How many instances are required to create a replica set?
A minimum of three instances is required to form a replica set. Out of these three, one is the primary node and the rest two are the secondary nodes. All the write operations are handled by the primary node and journaled in a file called oplog.
What happens when a read operation fails?
The read operations can be balanced between the secondary nodes so that the load does not affect the primary node. If the primary node fails, one of the secondary nodes takes its position and starts performing all the writes. And when the failed node is restored, it will now run as one of the secondary nodes.
What is MongoDB replication?
As the name says, MongoDB replication means instances that maintain the same data set. It contains several data bearing nodes and optionally one arbiter node. Out of all the data bearing nodes, only one of them is a primary node while the others are secondary nodes. A primary node can do all the write operations.
What is a sharded cluster?
A sharded cluster consists of the following components: shard: They contain the subset of sharded data. Each shard can be deployed as a replica set. mongos: They act as a query router. They also provide an interface between client applications and a sharded cluster.
What is secondary node?
The secondary nodes replicate the primary one and apply the operations to their respective dataset. When the data is reflected in the second one it also changes on the primary dataset. If the primary node is not available then the secondary nodes from themselves can elect one of them as a primary node.
What is a shard cluster?
A Sharded Cluster means that each shard of the cluster (which can also be a replica-set) takes care of a part of the data. Each request, both reads and writes, is served by the cluster where the data resides. This means that both read- and write performance can be increased by adding more shards to a cluster.
How many nodes are there in a Mongo cluster?
Put another way, you Replicate shards; a data-set with no shards is a single 'shard'. A Mongo cluster with three shards and 3 replicas would have 9 nodes. 3 sets of 3-node replicas.
How many servers are needed to split 75GB?
When you want to split your data of 75GB into 3 shards of 25GB each, you need at least 6 database servers organized in three replica-sets. Each replica-set consists of two servers who have the same 25GB of data.
What is a replica set?
A Replica-Set means that you have multiple instances of MongoDB which each mirror all the data of each other. A replica-set consists of one Master (also called "Primary") and one or more Slaves (aka Secondary).
Do write operations always take place on the master of the replica-set?
But write-operations always take place on the master of the replica-set and are then propagated to the slaves, so writes won't get faster when you add more slaves. Replica-sets also offer fault-tolerance. When one of the members of the replica-set goes down, the others take over.
Can a shard be a mongod instance without replication?
This is not required. When you don't care about high-availability, a shard can also be a single mongod instance without replication. But for production-use you should always use replication.
What is replication in data?
replication creates additional copies of the data and allows for automatic failover to another node. Replication may help with horizontal scaling of reads if you are OK to read data that potentially isn't the latest.
Can you scale reads in MongoDB?
It's primarily meant for redundancy, although you can scale reads by adding replica set members. That's a little complicated, but works very well for some apps. Sharding sits on top of replication, usually. "Shards" in MongoDB are just replica sets with something called a "router" in front of them.
