Basically and in most cases: yes. There are some notable exceptions to this rule (see Scrutinizers post #10 for such exceptions), but in general: what you try to achieve with disk striping a modern SAN box already does itself internally. There is no sense in doing it twice. If you are particularly unlucky (well, i agree, this is more a theoretical possibility) your own striping and the striping of the SAN box will overlay and create a Moiré-like effect that de-stripes your disk access.

I have once written a lengthy article about performance tuning, which i suggest you to read. Maybe it answers a few questions you might have.

The VNX is a small platform and i haven't worked with it but i suppose its frontend is not all that sophisticated. Therefore it might be worthwile to examine other aspects of disk access as well if the need of performance tuning arises: queue sizes, the distribution of block sizes in your typical load, data hotspots (maybe suggesting multitiered disk architectures with SATA-disks on one end and FC-disks or even SSDs on the other) or some other measures.

As Scrutinizer said so rightly: in performance tuning it always depends and one size never fits all.

I hope this helps.

bakunin