High availability (HA) tegese tetep database kasedhiyan sanajan ana gagal — liwat replication (standby replicas), automatic failover (ngowahi replica nalika primary gagal), lan architecture kang leres. Tujuan: kurangi downtime lan ilang data, amarga database outages bisa mateni kabeh aplikasi.
Fondasi: replication + automatic failover
Primary ──(streaming replication)──▶ Standby replica(s)
If the PRIMARY fails:
→ a STANDBY is automatically PROMOTED to become the new primary (FAILOVER)
→ the application reconnects to the new primary → minimal downtime
→ Without HA, a primary failure = total database outage = application down.
