active_instance_count behavior
- From: John D Parker <orclwzrd@xxxxxxxxx>
- To: oracle-l <oracle-l@xxxxxxxxxxxxx>
- Date: Tue, 14 Nov 2006 12:22:08 -0800 (PST)
Ok, in a 2 node RAC 9.2.0.5(yes, I know, don't ask). We have an active/passive
configuration with active_instance_count=1 set in both instances. This makes
instance prd1 the primary. My question hinges around behavior of block
mastering and cache coherency. In normal active/active RAC, each node "masters"
approx half the datablocks. Does this behavior change when I have a primary
node? I would think i would. However, I can't find any docs one way or the
other. With a Primary node and blocks being mastered like in active/active, the
primary node would be continually asking the passive node for blocks which
seems very inefficient. It would make more sense for the primary node to master
all the blocks and behave much like a pre 8.1.7 OPS node. Any thoughts here?
I'd really like to see some docs one way or the other but I can't seem to
locate any.
John Parker
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