“Write aside size” for LUNs on Clariion

I have been reading the great EMC book "Information Storage and Management Storing, Managing..." and I want to reconcile a term I read in the book with a configuration on the Clariion.

According to the book “Write aside size” is a configurable max size of an I/O request that is allowed to write to cache before writes are sent directly to disk.

Where do I configure this for LUNs on the Clariion? If possible could you give me an example in navisphere and the navicli? I could not find anywhere to configure this setting.