Question about ghost cells in parallel processing

vishwas

I have a 3-D grid in which there are 98 blocks. This grid was created using Gridgen. It will be processed using the INCA code prepared by Amtec engineering. It will be processed on one of the linux clusters at Sandia labs. I do not know any thing about the cluster and parallel processing. All I know is there a two ghost cells to be created at the boundaries of the blocks. But my question is are the ghost cells created at all the boundaries for all the blocks for parallel processing?

or

Ghost cells are created only at the boundary of the grid?

or

Ghost cells are created at all the boundaries of the blocks except for the boundaries of the grid?

Thank you