I have an external RAID0 array that I use for media production on my MacBook Pro. It is a 2-disk Thunderbolt unit from LaCie (Big2). I chose to stripe the data for performance. Considering the type of data I will be reading/writing from the array (mostly large-block, sequential) would it be better to just have a single volume or partition into two? I plan on dumping sample libraries as well as project files on it. Any performance impact with partitioning?
The only benefit to partitioning is to allow the operating system to treat the different partitions in different ways. For example, if you have one partition dedicated to a page file, sometimes some systems might benefit by having a dedicated partition so that the operating system doesn't need to deal with fragmentation caused by little files. However, you have proposed nothing that would really provide a benefit. You simply proposed multiple partitions. All that really does is prevent the operating system from writing some data into some part of the hard drive, because that part isn't within certain boundaries.
If there is going to be any benefit, we would need more details from the plan, like what type of data you propose to go in each specific partition. As the question is currently phrased, you mentioned some type of data, but haven't said how that will differ from any other data that will be getting used on the drive.
Just breaking it up into two partitions isn't likely to make things go lots faster.
Much of the answer on this would depend on whether your RAID is a hardware or software setup.
Software RAIDs are pretty terrible, in terms of performance. (and actually, MANY hardware RAIDs are equally slow).
Partitioning in itself won't make a tremendous difference in terms of transfer/copy performance, though it might help you long-term in maintenance (easier to format a volume when you've got it backed up elsewhere, etc)..