**2.8 Content Node (C-node) failure sense and replace**

When the event of C-Node failure occurs, co-related P-Node detects C-Node status by its response behavior. For example, C-Node (A/B) is mounted by P-Node (A/B), therefore, P-Node (A/B) detects C-Node (A/B) failure by no response or reply timeout. P-Node (A/B) single casts the message of call extra C-Node via C-DF. If an unassigned C-node is existing, then this C-node broadcasts the status to related C-Node in trio group. The nearest C-Node becomes the new member of C-Node trio group and starts to communicate with three as new trio group. The application is stored another size of C-Node with latest data, C-Node (B/C) provides "Storage partition "B" and C-Node (C/A) supplies storage partition "A" Thus, data duplication is time consuming work but this event runs on only C-DF. Therefore, seeing from out band requester, it is hidden internal task and less impact for out band service. This is one of the advantages by dual data field design. After duplication event is finished, New C-node (A/B) is released to P-Node (A/B). Even before complete this duplication event; other two of C-Nodes with three P-Nodes can sustain the operation without any service interruption.
