Hi,
I'm about to get a maxed out 27" Retina 5K display iMac along with FCPX and Motion 5. I'm shooting in both XAVC Long and 4K formats with a Sony PXW-X70. I also use a HD GoPro on occasion. My videos are anywhere from 10 minutes to 1 hour long. I will be using effects, music, plugins and some transitions. I do have some video editing experience coming from Sony Vegas Pro, but now I’m transitioning to the aforementioned. I need help in regards to proper hard drive setup. The following is what I believe I would need;

OS Hard Drive - iMac for all software
Editing Hard Drive - Pegasus2 R8 24TB (RAID 5) PROMISE Pegasus2 R8 24TB (8 by 3TB) Thunderbolt 2 RAID System - Apple (http://www.apple.com/shop/product/HE154VC/A/promise-pegasus2-r8-24tb-8-by-3tb-thunderbolt-2-raid-system)
Video Storage Hard Drive (raw video) - 4TB
Master Hard Drive (finished video) - 4TB

I need to know how to properly setup (aim) the hard drives within FCPX and Motion for a smooth workflow? If you have any other suggestions for hard drive setup and/or workflow, I would sincerely appreciate it. Thanks, Ray

Sounds a great setup - maybe a tad overkill for low-bitrate 4K and 1080p IMHO but you'll definitely have room to grow! If money is an issue, you could easily get by with the Pegasus R4 or R6. Even my 1st Gen Pegasus has been great!

Pointing FCPX to the right drive is easy - you just need to do 1 of 2 things:

1 - If you store your video footage inside the FCPX Library package files, just make sure the libraries are stored on the external Pegasus drive. Final Cut manages the footage for you. This is the way I like to work.

2 - If you store your video footage outside of the FCPX Library package files, just make sure the Library and the external video files are both stored on the external Pegasus drive.

All rendering will be done to the Library file and wherever you have that stored, so keep your library on the fast external storage. Make sense?

Thanks...... Yes, your reply makes sense. Please correct me if I'm wrong..... I believe you're saying use the Pegasus as my editing external drive for both, Libraries and raw video storage. If this is correct, does the raw video remain raw while editing it in the Library structure? I've been under the impression of copying and moving raw video from a different external hard drive into the Pegasus for editing. By doing so, the raw video would be left in it's original state, unedited. Thanks again, I sincerely appreciate all your help. Ray