RTR Server Types
one node can contain the primary servers for one key range and standby servers for another key range to balance the load across systems. This allows the nodes in a cluster environment to act as standby for other nodes without having idle hardware. When setting up a standby server, both servers must have access to the same journal.
Figure 1–15 Standby Servers
Terminals | Frontends (FE) |
| FE |
Client
FE
Client
FE
Client
Routers (TR) | Backends (BE) Database (DB) |
BE
Server
BE | DB |
Standby
TR
Transactional shadow server
The transactional shadow server places all transactions recorded on the primary server on a second database. The transactional shadow server can be at the same site or at a different site, and must exist in a networked environment.
A transactional shadow server can also have standby servers for greater reliability. When one member of a shadow set fails, RTR remembers the transactions executed at the surviving site in a journal, and replays them when the failed site returns. Only after all journaled transactions are recovered does the recovering site receive new online transactions. Transactional shadowing is done by partition. A transactional shadow configuration can have only two members of the shadow set.
Shadow servers are servers on separate backends which handle the same transactions in parallel on identical copies of the database.
Introduction
