Optimal configuration of holes in a tube

[shantzzz]

Given a tube that requires a series of holes to be drilled into it, in general terms, what would be the optimal pattern/shape/spacing of holes to maintain structural integrity, particularly against a force acting in an axial direction ie, on the end of the tube? That is, to prevent buckling?

 

[anorlunda]

The better the quality of your question, the better we can answer. Based on what you said, only a very general answer is possible. Space them a widely as possible.