Migrate a cluster (TAR/ZIP)

This example shows how to migrate a v4.4 cluster to v5.x.
Migration to Neo4j 5 is supported only from version v4.4.

It is recommended to read the following pages before continuing:

The following example steps assume that the environment has three cluster members on v4.4 version and that their binaries, config file, and data are stored in the default locations.

Prepare the v4.4 cluster for migration

Prepare the v4.4 cluster for migration by recreating the indexes and the index-backed constraints to match the new index types, and by backing up each of your databases.

Recreate indexes and index-backed constraints

In v5.0, the BTREE index type is no longer available. Therefore, it is recommended to recreate all your BTREE indexes and index-backed constraints with index providers native-btree-1.0 or lucene+native-3.0 before switching to v5.x. During the migration, v5.x checks whether each BTREE index and index-backed constraint has an equivalent type of index and provider, and drops them.

What type of index to use instead of BTREE?

In most cases, RANGE indexes can replace BTREE. However, there might be occasions when a different index type is more suitable, such as:

  • Use POINT indexes if the property value type is point and distance or bounding box queries are used for the property.

  • Use TEXT indexes if the property value type is text and the values can be larger than 8Kb.

  • Use TEXT indexes if the property value type is text and CONTAINS and ENDS WITH are used in queries for the property.

If more than one of the conditions is true, it is possible to have multiple indexes of different index types on the same schema. For more information on each index type, see Operations Manual v5.0 → Index configuration.

Steps

  1. Recreate each of your BTREE indexes on the same schema but using the new type (RANGE, POINT, or TEXT) as per your use case. The following example creates a range index on a single property for all nodes with a particular label:

    CREATE RANGE INDEX range_index_name FOR (n:Label) ON (n.prop1)

  2. Recreate each of your index-backed constraints with index providers native-btree-1.0 or lucene+native-3.0 on the same schema but with the new provider. The following example creates a unique node property constraint on a single property for all nodes with a particular label. The backing index is of type range with range-1.0 index provider.

    CREATE CONSTRAINT constraint_with_provider FOR (n:Label) REQUIRE (n.prop1) IS UNIQUE OPTIONS {indexProvider: 'range-1.0'}

  3. Run SHOW INDEXES to verify that the indexes have been populated and constraints have been created with the correct index provider.

For more information about creating indexes, see Cypher Manual → Creating indexes.

Backup each of your databases

You can back up all databases from a single v4.4 cluster member.

To ensure the databases do not get updated during the backup, put them into read-only mode using the Cypher command ALTER DATABASE <databasename> SET ACCESS READ ONLY. Run the Cypher command SHOW DATABASES YIELD * and choose the member that is up-to-date with the last committed transaction on all databases as a backup source.

On an up-to-date member of the v4.4 cluster

  1. Create a directory to store backups. These steps use /migration-backups.

  2. Run the neo4j-admin backup command to back up each of your databases.

    • All databases that you want to back up must be online.

    • The command must be invoked as the neo4j user to ensure the appropriate file permissions.

    • Use the option --include-metadata=all to include all roles and users associated with each of your databases.

    		 
    neo4j-enterprise-4.4/bin/neo4j-admin backup --database=<databasename>  --backup-dir=/migration-backups --include-metadata=all

    The result is a folder for each database, called <databasename> and located in the /migration-backups folder, and a metadata script for each database, located in migration-backups/databasename/tools/metadata_script.cypher. For more information about the neo4j-admin backup command, see Operations Manual → Back up an online database.

On each member of the v4.4 cluster

Stop the Neo4j DBMS:

Alternatively, you can postpone the downtime of your v4.4 cluster until the very end if you can prepare the v5.x cluster on separate servers or make sure the ports do not conflict. This way, the databases in the v4.4 cluster will be available in READ ONLY mode while you prepare the new cluster.

 
neo4j-enterprise-4.4/bin/neo4j stop

Set up the v5.x cluster

Prepare the v5.x cluster for the migration

On each v5.x server

  1. Make sure that you are using Java 17.

  2. Download v5.x TAR or ZIP from Neo4j Download Center and unpack it.

  3. Copy the neo4j.conf file from the 4.4 installation and paste it into the /conf directory of the 5.x installation to replace its neo4j.conf file.

  4. Migrate the v4.4 configuration file to a v5.x-compatible format.

    The Neo4j Admin commands must be invoked with the same user as Neo4j runs as. By default, this user is called neo4j. This guarantees that Neo4j will have full rights to start and work with the database files you use.

    		 
    neo4j-enterprise-5.x/neo4j-admin server migrate-configuration

  5. Verify that the configuration file looks as expected.

    It is strongly recommended to read up on the new 5.x settings to fully take advantage of the v5.x features.

    Refer to Operations Manual → Set up a cluster and update the settings accordingly. In particular:

    • Make sure all the settings within the dbms and database namespace are the same across all servers. The server settings are the only settings that may vary.

    • It is required to explicitly set a port for all advertised addresses (except server.default_advertised_address) as they will no longer default to the corresponding listen address port.

  6. Copy all the files used for encryption, such as private key, public certificate, and the contents of the trusted and revoked directories from neo4j-enterprise-4.4/neo4j-enterprise-4.4/certificates/ to neo4j-enterprise-5.x/new/neo4j-enterprise-5.x/certificates.

  7. If you are using custom plugins, make sure they are updated and compatible with Java 17. Place them in the respective /plugins directory.

  8. Once your new servers are set, start each of them by running:

    neo4j-enterprise-5.x/bin/neo4j start

Migrate the database backups

You migrate the database backups only to one of the new servers.

On v5.x server a

  1. Use the neo4j-admin restore command to restore each of your databases except the system database:

    Assuming that neo4j is the default database and you want to restore the v4.4 neo4j database backup, first, you need to run DROP DATABASE neo4j IF EXISTS.

    		 
    neo4j-enterprise-5.x/bin/neo4j-admin database restore <databasename> --from-path=/migration-backups/<databasename>

  2. Migrate the <databasename> database:

    neo4j-enterprise-5.x/bin/neo4j-admin database migrate <databasename>

  3. Run SHOW SERVERS YIELD address, serverId to retrieve the server ID for server a.

  4. Recreate each of your migrated databases using one of these options:

    • If you have set the number of primaries and secondaries for your databases using initial.dbms.default_primaries_count (default is 1) and initial.dbms.default_secondaries_count (default is 0) settings, run the command:

      CREATE DATABASE <databasename> OPTIONS {existingData: 'use', existingDataSeedInstance: '[ServerId for a]'}

    • If you have not specified the number of primaries and secondaries for your databases, or if you wish to override the default values, specify the topology when recreating the databases:

      CREATE DATABASE <databasename> TOPOLOGY [desired number of primaries] PRIMARIES [desired number of secondaries] SECONDARIES OPTIONS {existingData: 'use', existingDataSeedInstance: '[ServerId for a]'}

      If you do not specify the number of primaries and secondaries, all databases will be on the same server.

  5. (Optional) Restore the roles and privileges associated with each of your databases by running the respective metadata script neo4j-enterprise-5.x/data/scripts/databasename/restore_metadata.cypher, which the neo4j-admin restore command outputs, by using Cypher Shell:

    Using cat (UNIX)
    cat neo4j-enterprise-5.x/data/scripts/databasename/restore_metadata.cypher | bin/cypher-shell -u user -p password -a ip_address:port -d system --param "database => 'databasename'"
    Using type (Windows)*
    type neo4j-enterprise-5.x\data\scripts\databasename\restore_metadata.cypher | bin\cypher-shell.bat -u user -p password -a ip_address:port -d system --param "database => 'databasename'"

  6. Run REALLOCATE DATABASES to evenly distribute your databases among the servers.

  7. (Optional) If you have kept your 4.4 cluster running while setting up the new one, you can stop it now.

  8. Remove the old installations.

Monitor the logs

The neo4j.log file contains information on how many steps the migration will involve and how far it has progressed. It is advisable to monitor this log.