HA Deployment
An HA deployment is a production environment run as an active / warm-standby pair: two Linkiir servers sharing one working directory and one log database, with a front door sending clients to whichever is active. If the active server fails, the standby promotes itself in about half a minute and no messages are lost.
How it differs from a single-server PROD environment
| PROD | HA | |
|---|---|---|
| Linkiir servers | 1 | 2, one active at a time |
| Working directory | Local | Shared, one directory both servers open |
| Log database | PostgreSQL or MS SQL | PostgreSQL or MS SQL, reachable from both |
| Broker | External cluster | External cluster, three nodes |
| Server failure | A maintenance event | A failover of seconds |
| License | Enterprise | Enterprise with the HA feature |
Everything else is the same: the same release, the same projects, the same import and export path between environments.
Full documentation
The High Availability section covers it in depth:
| Page | Covers |
|---|---|
| High Availability | What HA protects against, and what it does not |
| Terminology | Active, standby, failover, failback, quorum, RPO and RTO |
| Licensing | One Enterprise license with the HA feature per pair |
| Architecture | The design, key components, and the failover sequence |
| System Requirements | Sizing, shared storage, database, broker, ports |
| Topologies | The five supported deployment shapes |
| Using the HA Settings | The High Availability page: enable HA, name the servers, step down |
| Operating an HA Pair | Testing a failover, patching without downtime, monitoring |
| Backup and DR | Why HA is not a backup, and how DR differs |
| Planning Your Deployment | What to decide and prepare before the build |
HA is not a backup
Both servers read one copy of your data, so a deletion or a bad change affects both at once. An HA deployment still needs instance backups, a remote per project, and database backups. See Backup and Restore.