Stopping, Starting, Terminating, and Reviving Eon Mode Database Clusters
Stopping and Starting a Database Cluster
When you stop your database cluster, you shut down the nodes in the cluster. Shutting down the cluster is an additional step beyond just shutting down the database. When you shut down the cluster in cloud environments, the node's instances no longer run but are still defined in the cloud platform. You can quickly restart the cluster and database when you need to use it again.
Stopping the database cluster is the best option to use when you will not need it for a short to medium time frame. For example, if no one accesses your database on weekends or holidays, you may consider stopping the cluster.
You save money when you shut down your database cluster in cloud environments. Stopped clusters do not consume expensive CPU resources. Stopped clusters can still cost you money, however. If you configured your nodes with persistent local storage, your cloud provider usually still charges a small amount to maintain that storage space.
Terminating and Reviving a Database Cluster
Terminating a database cluster frees up the resources used by the database cluster's nodes.
On a cloud platform, terminating the database cluster deletes the node's virtual machine instances. The database's data and catalog remain stored in communal storage. You can restart the database by reviving it. When you revive a database, you provision a new database cluster and configure it to use the database's data and metadata stored in communal storage.
In an on-premises Eon Mode database, terminating the database cluster usually means shutting down the database and then repurposing the hardware that the nodes ran on.
Terminating the database cluster is the best option for when you will not need the database for an extended period (or if you are unsure whether you will ever need the database again). As long as you do not delete the communal storage location, you can get your database running again by reviving it.
To revive a database, you create a new Vertica Eon Mode cluster and configure it to use the database's communal storage location. The easiest way to revive a database in the cloud is to use the Management Console. It provisions a new Eon Mode cluster for you, and then revives the database onto it.
Reviving a database takes longer than starting a stopped database. Even if you use the MC to automate the process, provisioning a new set of nodes takes much longer than just restarting stopped nodes. When the new nodes start for the first time, they must load data from communal storage from scratch.
Terminating the database cluster can save you more money over simply stopping the database when the database's nodes have persistent local storage. Cloud providers usually charge you a small recurring fee for the space consumed by persistent local storage on the nodes.
See Also