Database Reference
In-Depth Information
Sharding the configuration server failure
To distribute the whole dataset to different machines and servers, that is, horizontal scaling,
MongoDB provides you with the sharding feature. Using this feature, you can split the
database into different pieces in separate servers. In the next chapters, we will learn more
about this feature in detail.
MongoDB uses configuration servers to store the configuration for the sharding settings
and relations between members. For the production environment, these configuration serv-
ers are exactly three in number.
If one or two distinct configuration servers become unavailable, the clustering works prop-
erly, but it cannot create more chunks from the dataset, which means that it will be read-
only.
Chunks are pieces of database in separate machines, and MongoDB splits the database into
chunks of data based on a sharded key. MongoDB creates chunks from the database after
write operations based on the given sharded key.
If all three configuration servers become unavailable, the cluster will be unavailable as
well. You should replace the configuration servers as soon as possible. Then, the cluster
will continue to use the configuration servers and work properly.
We will talk about sharded keys and chunks in detail in the next chapters.
