Error: Node Unable to Communicate with Cluster Ready Services in Oracle RAC
Oracle DBA Guide to ORA-Error Cluster Communication Issues
In an Oracle RAC environment, maintaining stable cluster communication is critical. One common ORA-error scenario Oracle DBAs face is when a node cannot communicate with Cluster Ready Services (CRS). This leads to service interruptions, node eviction, and database availability risks.
Errors like CRS-4535, CRS-4530, and CRS-4534 indicate that one or more nodes in the cluster cannot communicate properly with CRS, CSS daemon, or Event Manager. This situation must be handled immediately by an experienced Oracle DBA to prevent downtime.
Why This ORA-Error Happens
Common reasons include:
✔ Network interconnect failure between RAC nodes
✔ Clusterware service crash or resource failure
✔ Incorrect Oracle Grid Infrastructure configuration
✔ OS-level resource exhaustion (memory, CPU, disk)
✔ Voting disk or ASM communication problems
✔ Firewall or hostname resolution issues
Error –
CRS-4535 / CRS-4530 / CRS-4534 Error: Node Unable to Communicate with Cluster Ready Services in Oracle RAC
[grid@node2 ~]$ crsctl check cluster -all
************************************************************ node1: CRS-4537: Cluster Ready Services is online CRS-4529: Cluster Synchronization Services is online CRS-4533: Event Manager is online ************************************************************ node2: CRS-4535: Cannot communicate with Cluster Ready Services CRS-4530: Communications failure contacting Cluster Synchronization Services daemon CRS-4534: Cannot communicate with Event Manager ************************************************************
Solution
[root@node2 ~]# cd /u02/app/grid/product/19C/dbhome/bin
[root@node2 bin]# ./crsctl start cluster
CRS-2672: Attempting to start 'ora.cssd' on 'node2'
CRS-2672: Attempting to start 'ora.diskmon' on 'node2'
CRS-2676: Start of 'ora.diskmon' on 'node2' succeeded
CRS-2676: Start of 'ora.cssd' on 'node2' succeeded
CRS-2672: Attempting to start 'ora.ctssd' on 'node2'
CRS-2672: Attempting to start 'ora.cluster_interconnect.haip' on 'node2'
CRS-2676: Start of 'ora.ctssd' on 'node2' succeeded
CRS-2676: Start of 'ora.cluster_interconnect.haip' on 'node2' succeeded
CRS-2672: Attempting to start 'ora.asm' on 'node2'
CRS-2676: Start of 'ora.asm' on 'node2' succeeded
CRS-2672: Attempting to start 'ora.storage' on 'node2'
CRS-2676: Start of 'ora.storage' on 'node2' succeeded
CRS-2672: Attempting to start 'ora.crsd' on 'node2'
CRS-2676: Start of 'ora.crsd' on 'node2' succeeded
[root@node2 bin]#
Conclusion
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