Clusterware

The Oracle Exadata Deployment Assistant (OEDA) is the mandatory tool for configuring and deploying Oracle Grid Infrastructure and Oracle Database on Exadata hardware. It generates the configuration XML that drives the automated install.sh deployment script, eliminating manual installation error. This article covers the full OEDA workflow — from GUI configuration through XML generation to deployment execution — with real-world examples. What OEDA Does and Does Not Do OEDA does: Configure networking (public, private/InfiniBand/RoCE, management/ILOM, admin) Define cluster nodes, ASM disk groups, and storage configuration Configure Grid Infrastructure (GI) and Oracle Database parameters Generate the install.sh script and all supporting XML/config files Validate the configuration before deployment (via --check) OEDA does not: ...

Cache Fusion is the technology that allows Oracle RAC nodes to share a single consistent view of the database buffer cache across all instances. Without it, every cross-instance read or write would require a disk I/O. With it, dirty blocks travel directly from one instance’s buffer cache to another across the private interconnect. Understanding how this works is the foundation for diagnosing RAC-specific performance problems. The Problem Cache Fusion Solves In a traditional single-instance Oracle database, the buffer cache is authoritative. When an instance needs a block, it either finds it in cache or reads it from disk. In RAC, multiple instances have their own buffer caches, but they share the same datafiles. Without coordination, Instance A and Instance B could each have different versions of the same block in cache — a consistency nightmare. ...

The private interconnect is the central nervous system of an Oracle RAC cluster. Poor interconnect performance cascades directly into gc cr block 2-way, gc current block 2-way, and related wait times. Before tuning any Oracle parameter, the interconnect hardware and OS configuration must be validated. This article covers the full stack — from NIC configuration to Oracle’s use of the network. Interconnect Architecture Options Technology Bandwidth Latency Use Case 1 GbE 1 Gb/s ~100–200μs Small, low-traffic clusters only 10 GbE 10 Gb/s ~20–50μs Standard current minimum 25 GbE 25 Gb/s ~10–20μs High-throughput OLAP/mixed RoCE (RDMA over Ethernet) 25–100 Gb/s ~1–5μs Modern Exadata, high-performance InfiniBand (EDR) 100 Gb/s <1μs Pre-X8M Exadata, HPC For new deployments, 25 GbE minimum is the practical recommendation. On Exadata X8M+, RoCE is the default interconnect technology, delivering near-InfiniBand latency over standard Ethernet infrastructure. ...