CRS-2409: The clock on host is not synchronous with the mean cluster time

I got ” CRS-2409: The clock on host is not synchronous with the mean cluster time ”  error in Oracle database.

 

CRS-2409: The clock on host is not synchronous with the mean cluster time

 

Details of error are as follows.

Grid Infrastructure alert.log shows messages:

CRS-2409:The clock on host <hostname> is not synchronous with the mean cluster time. No action has been taken as the Cluster Time Synchronization Service is running in observer mode.

The clock is synchronized properly using Network Time Protocol(NTP) on all servers using as shown in output from:

$ cluvfy comp clocksync -n all -verbose

....
....
Result: Clock synchronization check using Network Time Protocol(NTP) passed

Oracle Cluster Time Synchronization Services check passed

Verification of Clock Synchronization across the cluster nodes was successful.

 

Introduced in 11.2 release.

 

The CTSS will generate a CRS-2409 error if the clock difference is greater than 1 ms between this node and the reference node in the cluster.
This is shown even though CTSS is in observer mode and clock synchronization is being done externally (e.g. ntp). As ntp is setup correctly as shown in above cluvfy output you can ignore this warning.

Development changed the code in the 11.2.0.3.0 release so CTSS will still detect the clock difference, but generate the alert messages less frequently.

In addition, below reported bug in 11.2.0.4 fixed in 12.2 and fix included in OCW PSU 12.1.0.2.160419 onwards, for moving the messages from GI alert logs

Bug 18952857 – OPTIMIZE CTSS MESSAGES CRS-2408 AND CRS-2409

 

 

Second case is as follows.

Cluster alert log on one of the nodes shows the following  message

[ctssd(9534)]CRS-2409:The clock on host <hostname>  is not synchronous with the mean cluster time
. No action has been taken as the Cluster Time Synchronization Service is running in observer mode.

What does this message mean?

This is not an error. ctssd is reporting that there is a time difference and it is not doing anything about it as it is running in observer mode.

 

The Cluster Time Synchronization Service (CTSS) is one of the new processes in the Oracle Clustware 11gR2 layer , the CTSS is installed during the GRID infrastructure installation.

CTSS Daemon is responsible for the time management within the cluster. It makes sure each node in the cluster is using the same time. First, CTSS will determine if a Network Time Protocol (NTP) daemon is running in the system and if NTP is not running, then  CTSS will run in active mode and perform the same task as the NTP daemon. If NTP daemon is running,  CTSS will be started  in observer mode.

– We need to check if there is a time difference on the nodes.
– We need to make sure ntp is running properly and with -x option

 

 

 

 

 

Do you want to learn Oracle Database for Beginners, then read the following articles.

Oracle Tutorial | Oracle Database Tutorials for Beginners ( Junior Oracle DBA )

 

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About Mehmet Salih Deveci

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