A simple guide for checking the health, setup, and performance of Oracle Real Application Clusters (RAC).

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🖥 RAC Configuration & Nodes

olsnodes → List all RAC nodes.

olsnodes -n → List nodes with numeric IDs.

olsnodes -i → Show VIP addresses.

olsnodes -p → Show public node names.

crsctl query crs activeversion → Show active Clusterware version.

crsctl query crs softwareversion <node> → Version on a specific node.

crsctl stat res -p → View detailed parameters for all resources.

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⚙️ Cluster & Database Management

crsctl stat res -t → Status of all cluster resources.

srvctl config database -d <db> → DB configuration.

srvctl status database -d <db> → DB status across RAC nodes.

srvctl status instance -d <db> -i <inst> → Status of a single instance.

srvctl config service -d <db> → List DB services.

srvctl status service -d <db> → Service status across nodes.

srvctl config scan → SCAN configuration.

srvctl status scan → SCAN listener status.

srvctl status listener -n <node> → Listener status per node.

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📊 Instance & Session Checks (SQL*Plus)

SELECT INSTANCE_NUMBER, INSTANCE_NAME, HOST_NAME, STATUS FROM GV$INSTANCE;

SELECT NAME, VALUE FROM GV$PARAMETER WHERE NAME LIKE ‘%instance_number%’;

SELECT NAME, VALUE FROM GV$PARAMETER WHERE NAME LIKE ‘%thread%’;

SELECT * FROM GV$SESSION;

SELECT * FROM GV$LOCK;

SELECT * FROM GV$LOCK_TYPE;

SELECT INST_ID, BLOCKING_INSTANCE, BLOCKING_SESSION FROM GV$SESSION WHERE BLOCKING_SESSION IS NOT NULL;

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📈 RAC Performance & Cache

SELECT INST_ID, CLASS, CR_REQUESTS, CURRENT_REQUESTS FROM GV$CACHE_TRANSFER;

SELECT * FROM GV$GES_DEADLOCK;

SELECT * FROM GV$GES_BLOCKING_ENQUEUE;

SELECT * FROM GV$CURRENT_BLOCK_SERVER;

SELECT * FROM GV$CR_BLOCK_SERVER;

SELECT * FROM GV$GCS_MESSAGE;

SELECT * FROM GV$GES_RESOURCE;

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🌐 Interconnect & Network

oifcfg getif → View Oracle interface configuration.

ifconfig / ip addr → Network details (OS).

ping <private_IP> → Interconnect test.

traceroute <private_IP> → Trace interconnect route.

netstat -rn → Check routing table.

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📂 Logs & Health Checks

crsctl check crs → CRS health check.

crsctl query crs releasepatch → Clusterware patch level.

tail -f $GRID_HOME/log/<node>/alert.log → Clusterware log.

tail -f $ORACLE_BASE/diag/rdbms/<db>/<instance>/trace/alert_<instance>.log → DB alert log.

adrci → Interactive alert/log monitoring.

adrci show homes → List all ADR homes.

adrci show alert → Display alert logs.