Replication
overview
IBM®
Netezza® Replication Services 2.0.0.0 keeps a collection of
databases and global data identical across multiple, geographically dispersed Netezza Performance
Server (NPS) nodes deployed on Cloud Pak For Data System 2.0.1. IBM
Netezza Replication Services 2.0.0.0 provides disaster
recovery (DR) by keeping the NPS nodes at the replica(s) in sync with the NPS nodes at the
primary.
Introduction to IBM Netezza Replication Services 2.0.0.0S
Netezza Performance Server (NPS) nodes are redundant, fault-tolerant systems. Adding IBM Netezza Replication Services for disaster recovery improves the fault tolerance by extending redundancy across local and wide area networks.
Eventually consistent design, latency, and backlog
A replication set is consistent when SQL queries on one replication node of the group produce the same result on all replication nodes of the group. To keep databases on different nodes identical, IBM Netezza Replication Services uses the eventually consistent method.
Synchronization
IBM Netezza Replication Services uses two approaches to maintaining synchronization: SQL statement replication (by-SQL replication) and change value replication (by-value replication). The method that is used is based on whether the SQL transaction contains a deterministic value.
Replicated transactions and concurrency
Replicated transactions on a primary NPS node can execute with any mix of serializable isolation and snapshot isolation (relaxed serializability).
Replication queue manager
The replication queue manager component off-loads replication from the NPS node, providing storage capabilities and transport capabilities between replication queue managers that are used for the replication log and backups.