Hierarchical Voter: Read/Write Quorum Generation


This application  generates read/write quorum and displays color encoded nodes in a hierarchical tree. The display shows following:




Create/Reset Voter Tree   Click the button to create a new voter tree or reset the tree configuration to default.



Update Voter Tree    Click the button to modify number of child nodes at ith level.





Updating Read/Write Quorum: The  read and write quorums can be modified by setting state of nodes participating in Read or write quorum. To modify read quorum, double click on a leaf node ( any Green leaf node), its state would be set to faulty and the node color would change to Red.  The read  and write quorum panes   would be updated to reflect the node state and new quorum. Similarly double clicking a node in write quorum would trigger updates to Read and Write quorum panes.







The following snapshot displays default configuration of Hierarchical Voter  with 4 abstract node levels, with each node having 3 child nodes. The initial read quorum is 2.


Please scroll  the panes to right to view complete voter tree.



(Screen Snapshot of  Default Voter Configuration)


Top Pane Displays Read Quorum.

Middle Pane Displays Write Quorum.

Bottom Pane Displays  Minimal list  of Read Quorums covering each leaf node in at least once. Note: The quorum list doesn’t contain all possible permutations of read quorums. Also the  read quorum list ignores the current state of node while generating set of read Quorums. The graphical display however reflects the correct state of hierarchical voter with respect to state of leaf nodes.




























(Snapshot of Voter with 6 child nodes at last abstract node level:3  )