This section describes how to upgrade a Neo4j Causal Cluster.
It is recommended that your instance of Neo4j is kept up to date. Upgrading a Neo4j Causal Cluster to Neo4j 3.3.1 will ensure that you are provided with improvements in performance and security, as well as any latest bug fixes.
All upgrades should be approached with careful planning and testing.
Read Section 5.1, “Upgrade planning” thoroughly and perform all the steps listed there.
Neo4j 3.3.1 does not support rolling upgrades, so the upgrade process can involve significant downtime for the entire cluster.
If you have the infrastructure to support running the existing and the upgraded clusters at the same time, the downtime can be reduced to a small window.
Changes in a particular version
The details of a version change can be found in the Release Notes.
Neo4j does not support downgrades.
However, the steps described in this section are non-destructive.
If, for some reason, it is decided to not approve the upgrade and a rollback has to happen, you will put your non-upgraded
read/write mode and start up the cluster again.
Prepare the new cluster:
Make sure that the IP addresses of the new servers are reflected in the configuration files:
dbms.mode=CORE causal_clustering.initial_discovery_members=<YOUR SETUP>
Set your cluster to
Note: This step involves downtime.
On each server in the cluster:
Edit neo4j.conf and set
dbms.read_only to be
Perform the upgrade on one of the servers in the new cluster:
Save the prepared neo4j.conf into a temporary file on one of the servers in the new cluster:
neo4j-home$ cp neo4j.conf neo4j.conf.save
Edit neo4j.conf to make this a stand-alone server, and allow for upgrade:
Start up Neo4j 3.3.1.
Restore the original configuration file on this server:
neo4j-home$ mv neo4j.conf.save neo4j.conf
Prepare the cluster with the upgraded database. See Section 4.2.4, “Seed a Causal Cluster” for more information.
Restore the backup on each machine using
neo4j-home$ bin/neo4j-admin restore --from=/mnt/backup/graph.db-backup --database=graph.db --force