We don't have synonyms for petascale yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are pedascule, pascale and terascale.
(adj) :
A metric for objects on the scale of quadrillions (10¹⁵ or 1,000,000,000,000,000) of elements. Most often used for computer systems; a petascale computer system operates at speeds measured in petaflops and has memory measured in petabytes.
(adj) :
A metric for objects on the scale of quadrillions (10¹⁵ or 1,000,000,000,000,000) of elements. Most often used for computer systems; a petascale computer system operates at speeds measured in petaflops and has memory measured in petabytes.