I understand now, @superman101!
If you want to buy such a network attached storage, I'd recommend you search for an expert series NAS with at least 4 HDD bays in order to create the RAID 10 configuration. If you want build the NAS yourself, make sure you choose a motherboard that supports & incorporates a RAID controller that can support the RAID 10 configuration.
However, you should always make sure you backup your raw files or finished video files somewhere else as well. People often mistake that a RAID array is a solid backup solution, but it isn't. You should always make sure you have keep multiple duplicates of your files in various locations.
RAID 10 combines disk mirroring and disk striping to protect data. It is a great solution for high-performance storage where redundancy is vital. But it's not as fast as RAID 0, for example, if speed is what you seek. However, RAID 0 has no fault tolerance and no redundancy, which puts all the data you work with on that NAS in jeopardy.
NAS systems usually have their own file system & operating system, if it's connected through the network, your iMac or any other device/computer should be able to access it that way. The transfer speed will depend on how fast is your Internet/router connection and how you connect the NAS to it.
P.S. You need to know that NAS systems are not servers, they are a great storage solution to keep your files and access them from anywhere, but you won't be able to edit the files without downloading them on the computer first.
Let me know if you have more questions. Good luck!
SuperSoph_WD