HA Proxy Configuration for Online Backup
What are we trying to achieve?
Online backup should be scheduled to run periodically on a production cluster. You only need to run it on one instance, since each has its own full copy of the database. Because a full backup also runs a consistency check, and the copy itself does use some system resources, it is recommended to run this on a slave instance (in HA mode) or a follower or read-replica (in CC mode).
For incremental backups to work, you need to take a backup from the same instance each time and have transaction logs from the last backup. If you do not run from the same instance the store won’t match and it will fallback to taking a full backup. If you want to control which instance you take the backup from, you would need to modify this example or just take a backup directly to that instance without a proxy in between. If you are OK to fallback to full backup, this approach may work for you.
Causal Clustering: Directing online backup to a follower or read-replica
The sample configuration below defines a front-end where the backup utility will connect to the running database, and a set of instances
to check whether they are a slave currently. We assume that online backup is enabled in the
conf/neo4j.conf file as follows:
The haproxy.cfg file for Causal Clustering backup from a Follower would look like this:
defaults mode http timeout connect 5000ms timeout client 30000ms timeout server 30000ms # Available at http://localhost:8080/haproxy?stats listen admin balance mode http bind *:8080 stats enable frontend neo4j-backup mode tcp bind *:6362 default_backend cores-backup backend cores-backup balance roundrobin option httpchk GET /db/server/core/read-only HTTP/1.0 mode tcp server neo4j-1 neo4j-1:6362 server neo4j-2 neo4j-2:6362 server neo4j-3 neo4j-3:6362
To backup from a read-replica, replace the
option httpchk line with:
option httpchk GET /db/manage/server/read-replica/available HTTP/1.0
HA: Directing online backup to a slave
The haproxy.cfg file for HA mode would look like this:
defaults mode http timeout connect 5000ms timeout client 30000ms timeout server 30000ms # Available at http://localhost:8080/haproxy?stats listen admin balance mode http bind *:8080 stats enable frontend neo4j-backup mode tcp bind *:6362 default_backend slaves-backup backend slaves-backup balance roundrobin option httpchk GET /db/manage/server/ha/slave HTTP/1.0 mode tcp server neo4j-1 neo4j-1:6362 server neo4j-2 neo4j-2:6362 server neo4j-3 neo4j-3:6362
Assuming the haproxy DNS name is something like
neo4j-backup-slaves, the backup command would look like the following:
$ ./bin/neo4j-admin backup --name=backup.db --backup-dir /tmp/backups --from=neo4j-backup-slaves:6362
Or the now deprecated
$ ./bin/neo4j-backup -to /tmp/backups -host neo4j-backup-slaves -port 6362
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