NTP settings for RAC - Step vs Slew

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During Oracle RAC db installation prerequisite check, there is a validation raised on NTP configuration. Oracle needs NTP to be configured with "slew_always" option enabled, So what is this slew setting in NTP?

NTP can operate in two modes,
               1. Slew mode -- NTP will adjust time drift at a maximum rate of 500 microseconds persecond. This ensures that the server will not see any quick/large time differences which Oracle consider as a requirement.
               2. Step mode -- In this mode, clock can suddenly change time in large quantities to make any adjustment. Apparently this behavior can cause issues in db server operations.

Below is the configuration change required to enable slew_always on Solaris 11.3,
 svccfg -s svc:/network/ntp:default setprop config/slew_always = true





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