see Primus emc60253 "In excluding ???????? Celerra is following windows semantics at the protocol level. For Microsoft - ???????? : means 8 characters not taking into account '.' .. "excl=????????" is found to exclude not only the files fitting the format of Excel temporary files, but also files with four character names and a three character extension. A file like "abcd.txt" is excluded since the "." is counted as a character and the total string length is eight characters. .. In NAS 5.6 and above, "excl=????????" will exclude all files names with 8 characters - i.e. "abcdefgh" will be excluded just like "abcd.exe" is excluded.  In NAS 5.6 and above, "excl=>>>>>>>>" will exclude all file names with 1 to 8 characters, not including extension, that is, "abc" will be excluded just like "abcdefgh" is excluded."
I'm currently putting together a list of file extesions to exclude from AV scanning via Cava from our Celerra/VNX products.  One of the most common file types to exclude is "????????", however I can't help but wonder if this would exclude a file by the name of "viru.exe", "abcd.doc" (or a similarly named 8-character total length filename).  Is anyone able to shed any light on this please?
Cava exclusions list