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MongoDB for Oracle DBA’s Part 11 : Enabling Preferred Read on Standby (Secondary) Instances

As we know in ASM we can specificy the preferred read fail group to scatter the reads across the failgroups to reduce the read contention on single disk group. Similarly in MongoDB you can set to read the data from secondary servers i.e standby, In other words take this as active dataguard feature where you […]

MongoDB for Oracle DBA’s Part 9 : Node Evictions – Losing a Shard

In the previous post we saw when a node in replicaset lost, the secondary nodes become a primary and all data is available.

In this post we will see what if , if a shard is completely lost. A picture looks like this.

As the data is distributed across the shards, if a […]

MongoDB for Oracle DBA’s Part 9 : Node Evictions

In MongoDB the high availability is called as basic availability, means in event a primary replicaset lost , the secondary can become primary with in that replicaset. But when the whole shard is down (including all nodes within that replicaset) then there is no High Availability, the data is partially available with respects to the […]

MongoDB for Oracle DBA’s Part 7 : Adding a New Shard to existing Cluster in Standalone Server

In this post we will see how to Add a new shard shard2 and new replicaset rs1

Create Directories Create Config Files Start the instances in replicaset rs1 add the instances for replication to replicaset rs1 add the replicaset rs1 to shard

The final diagram in my single host, Mongos , MongoC, MongoD with replicaset […]

MongoDB for Oracle DBA’s Part 6 : Creating a Shard for ReplicaSet in Standalone Server

In previous post we saw, to create a replicaset like standby in standalone server.

Basically with a replicaset the read/writes can be achieved via primary node and secondary nodes are inaccessible, this creates a concurrency issues with single node cluster. So we create a shard i.e data partitioning across nodes. The data will be distributed […]

MongoDB for Oracle DBA’s Part 5 : Converting Standalone MongoDB Database to Single Replicaset in Standalone Server

In Previous post we saw, how to install MongoDB and Create a standalone database.

In this post we will see how to achieve high availability in MongoDB by using replicasets. In MongoDB the high availability is acheived by using replicaset as like Standby in Oracle. They are called as Primary and Secondary Replicaset. Whenever there […]

MongoDB for Oracle DBA’s Part 4 : Creating Standalone MongoDB Database

In this post, we will see how to create a standalone MongoDB Instance.

Installation is pretty straight forward just download and modify few configuration options and start the instance. This is just to prepare and know ourself, whilst the next posts will be continuation of this post , to convert the single instance to […]

MongoDB for Oracle DBA’s Part 1 – Features or Keywords Comparision

Welcome to first Post on MongoDB.

Given my experience over RDBMS during past decade, exploring the current NOSQL database technologies and keep ourself updated. This will not only help ourselves but also enable us to know where to use this, since majority NOSQL databases are not fit for everything, they are customised and fit […]