Leaf nodes in Flex cluster

Hi,
can somebody explain what leaf nodes in flex cluster are?from documentation I see that they are nodes which dont have access to storage and they communicate with hub nodes.
Can they have oracle db instances?If so how is data transfered between hub and leaf nodes?Through interconnect?Doesn't it overload the interconnect?
Thanks
Sekar

Sekar_BLUE4EVER wrote:
Thanks Aman...Still confused about this...Consider the following scenario
|       H1       |<-------> |        H2         |   <------> |       H3        |
|                   |              |                      |               |                    |
| L1 L2 L3 |              | L1   L2   L3   |               | L1 L 2 L3   |
| _________|              |___________|               |__________|
H depicts the hub nodes and L depict the leaf nodes.Assume each Hub node has 3 leaf nodes attached to them.
Suppose L1 connected to H1 needs a block and modifies it and after sometime L1 connected to H2 needs the same block then it must follow the same 2 way/3 way grant as in normal cache fusion right?
Does this actually increase the number of hops since the leaf nodes are not directly connected?
Do we have any control over the leaf node to hub node mapping or is it all automatically managed?
Thanks
The blocks are going to be accessed, modified at the Hub nodes only AFAIK as the Hub nodes are considered as DB Nodes. The Leaf Nodes are going to be considered as the Application Nodes. That's the reason, it's better to set up the instances running on the Hub Nodes only rather than the Leaf Nodes. Even if the instance runs on a Leaf Node, the communication is between the Hub and Leaf node only and it won't do any harm as both the nodes-Hub and Leaf(and the other nodes in the Leaf group) would be talking to each other directly. There is no VIP required on the Leaf Nodes so the connections by the database users would be only on the Hub Nodes, I guess and that means, the block movement would remain essentially the same.
The number of network hops are reduced as you won't be having a requirement to have too many Hub Nodes since each Hub node can connect to 64(?) Leaf Nodes. So essentially, in your case, you would need only 4 Interconnects (2 on one Hub Node and 1 each on the remaining two) for the private interconnect and just 3 network links for the storage for each Hub node.
I am not sure that I understood the last question of yours.
HTH
Aman....

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