Re: RAC nodes and date/time sync

On Thu, 15 Sep 2005 07:43:22 +0200, mea0730 wrote (in article <1126763002.595057.152610_at_g14g2000cwa.googlegroups.com>):

> How important is it for the time to be sync between nodes in a RAC
> cluster? Do they have to be within a microssecond, second, minute,..?
> or does it matter at all?

Think about this ... what happens if your app first uses instance a and does something with date/time and in the next phase happens to connect to instance b that is running behind instance a (in time). This could lead to transactions being done in the future ... (nice for a stock broker).

As far as I know locking is not based on the real clock time but on an internal clock that is not much more than a counter. Time to do synchronization with is not a very good option. What happens if the hardware gets a little quicker ? It will all get a bit messy. Read about cache fusion and how it works. It's good reading and also explains a bit about how RAC scales and why.

With kind regards / met vriendelijke groeten, Ronald

http://ciber.nl
http://homepage.mac.com/ik_zelf/oracle Received on Sat Sep 17 2005 - 06:02:02 CDT