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How Does Oracle ExaWatcher Decide When to Delete Old Logs?

  If you manage Oracle Exadata environments, you rely on ExaWatcher to quietly collect performance diagnostic data in the background. Because ExaWatcher is standardized across nodes, Database Administrators (DBAs) and Exadata Direct Engineers (DMAs) generally expect archive retention to look uniform across identically configured environments. However, a common point of confusion arises during capacity audits: Why does one Exadata environment purge files older than 30 days and stay around 1 GB, while another retains months of historical archives up to 2.4 GB - despite having the exact same ExaWatcher configuration? In this post, we break down a real-world troubleshooting case across Development ( DEV ), Integration ( TESTINT ), and Quality Assurance ( QA ) Exadata database nodes to uncover how ExaWatcher actually governs archive retention, the hidden filesystem triggers inside ExaWatcherCleanup.sh , and how to safely manage historical archives. The Mystery: Identical Conf...
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Benchmarking Oracle Database@AWS Exadata Dedicated: Backup & Restore Channel Scaling vs. Orchestration Overhead

 When designing disaster recovery (DR) architectures and tuning Recovery Point/Time Objectives (RPO/RTO) on Oracle Database@AWS (Exadata Dedicated) , database administrators intuitively look to RMAN parallel channel allocation. However, cloud-native managed database workflows wrap raw RMAN operations inside automated orchestration frameworks. Recent benchmark testing across 4-channel and 8-channel configurations reveals an important operational insight: the primary bottleneck is not RMAN data streaming, but the pre-flight and post-execution orchestration overhead. 1. Backup Performance Analysis: The 16-Minute Fixed Cost (Using ARS) In testing full database backups, scaling channels from 4 to 8 had virtually zero impact on the end-to-end elapsed time. Benchmark Data Metric 4 Channels  8 Channels  Delta / Impact Actual Backup Duration (RMAN) 03:03:05 – 03:06:39 ( 3m 34s ) 03:02:25 – 03:05:57 ( 3m 32s ) 2s difference (negligible) Total Duration (with Pre-checks) 22m 12...
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Optimizing RMAN Channels on Oracle Database@AWS Exadata Dedicated Infrastructure

 When managing Oracle Database deployments on Exadata Dedicated Infrastructure—including Oracle Database@AWS —backup throughput is directly influenced by how Recovery Manager (RMAN) allocates channels across compute nodes. By default, the automated tooling computes parallel channels based on available compute capacity (OCPUs or ECPUs). However, smaller test or QA databases with modest compute allocations often need faster backup windows. Understanding how Oracle allocates channels during backup versus restore operations is critical for sizing your environment and avoiding unnecessary CPU scale-up costs. OCPU vs. ECPU: Default RMAN Channel Allocation Rules Oracle’s managed backup frameworks dynamically calculate the default number of channels per compute node based on provisioned core capacity: ECPU vs. OCPU Metric Conversion:  1  OCPU = 4 ECPUs. Default Channel Formula:   Compute Ratio & Default Channel Sizing Oracle Database@AWS uses the following standard cor...
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How to Connect to the RMAN Recovery Catalog with Oracle Autonomous Recovery Service (ARS)

 Connecting to the ARS Recovery Catalog with RMAN When using Oracle Autonomous Recovery Service (ARS / DBRS) for database backups, the connection to the recovery catalog is secured via an auto-generated Oracle Wallet and configured TNS alias. To run manual RMAN operations (such as maintenance, reporting, or manual validation), you need to point your environment to the directory containing the ARS wallet/TNS configuration and connect via the catalog alias. Step 1: Locate and Set the TNS_ADMIN Directory First, identify the directory where your ARS configuration files ( tnsnames.ora , sqlnet.ora , and wallet files like cwallet.sso ) reside. On OCI Database environments (such as Base Database Service or Exadata), these are typically stored under the database cluster file system (ACFS) path. Export the TNS_ADMIN environment variable so RMAN knows where to look for network configuration and credential artifacts: # Verify the directory path containing your ARS credentials [oracle@dev-f...
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