Wednesday, December 30, 2009

Time difference between the RAC nodes is out of sync

If the time difference between the RAC nodes is out of sync (time difference > 30 sec) then it will result one of the following issues

1. CRS installation failure on remote node
2. RAC node reboots periodically
3. CRS Application status UKNOWN or OFFLINE

To avoid these issues configure NTP (Network Time Protocol) on both nodes using any one of the following methods

1. system-config-time or system-config-date or dateconfig

Type command system-config-time or system-config-date or dateconfig at terminal --> Click “Network Time Protocol” ->check “Enable Network Time Protocol” and select NTP server --> Click OK

Type command date with current date and time

3. /etc/ntp.conf
Update /etc/ntp.conf file with timeservers IP addresses and start or restart the ntp daemon
$ /etc/init.d/ntp start
$ /etc/rc.d/init.d/ntp start

Once RAC nodes are time sync you might need to shutdown and startup the CRS applications manually.
$ crs_stop ora.testrac1.ons
$ crs_start ora.testrac1.ons

In case if you encounter CRS-0223: Resource 'ora.testrac1.ons’ has placement error then stop and start all CRS Applications to resolve the issue.

$ crs_stop -all
$ crs_start -all

Satishbabu Gunukula


  1. Good information, nice post, thanks a lot

  2. Very good post on ntp. Both nodes of our RAC rebooted recently and Oracle recommended starting with ntpd -x option.

  3. The key is "-x" in /etc/sysconfig/ntpd

    If you are using NTP, and you prefer to continue using it instead of Cluster Time Synchronization Service, then you need to modify the NTP configuration to set the -x flag,

    Sunil Bhola

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