Geek Answers Handbook

What is meant by node in cassandra?

I am new to Cassandra and I want to install it. So far I have read a short article.

But there is one thing that I do not understand, and that is the value of "node".

Can someone tell me what a "node" is, what it is for, and how many nodes we can have in one cluster?

+7
cassandra
source share
3 answers

A node is the storage tier on the server.

Newer versions of Cassandra use virtual hosts or vnodes. The default is 256 servers per server.

Vnode is essentially a storage tier.

  • machine : physical server, EC2 instance, etc.
  • Server : Install Cassandra Each machine has one Cassandra installation. The Cassandra server starts basic processes such as snitch, delimiter, etc.
  • vnode : The storage tier on the Cassandra server. By default, the server has 256 vnodes.

Helpful advice:

If you are confused that the terminology of Cassandra (in old blogs, YouTube videos, etc.) was used inconsistently. In older versions of Cassandra, one Cassandra server was installed on each machine, and each server contained one node. Due to the 1-to-1-to-1 relationship between the host machine server in older versions of Cassandra, people previously used the terms machine, server, and node interchangeably.

+6
source share

Cassandra is a distributed database management system designed to process large amounts of data on many commodity servers. Like all other distributed database systems, it provides high availability without a single point of failure.

You can get some ideas from the description of the paragraph above. As a rule, when we talk about Kassandra, we mean the cluster of Kassandra, and not just one PC. A node in a cluster is a fully functional machine that is connected to other nodes in the cluster through a high internal network. All nodes work together to make sure that even if one of them fails due to an unexpected error, they, as a whole cluster, can provide a service.

All nodes of the Cassandra cluster are the same. There is no concept of a master node or subordinate nodes. There are several reasons for this design, and you can use it to get more details.

Theoretically, you can have as many nodes as you want in a Cassandra cluster. For example, Apple used the 75,000 nodes that serviced the Cassandra Summit in 2014.

Of course, you can try Kassandra with one machine. It still only works with one node in this cluster.

+5
source share

If you want to understand the terminology of Cassandra, then the following publication is a good reference:

http://exponential.io/blog/2015/01/08/cassandra-terminology/

-one
source share

More articles:


All Articles