They are independent hardware, but the data structure on them is not independent. This means that you will only get partial data if you only have parts of the array.
However, RAID 6 is very fault tolerant, and is therefore my go-to choice for RAID setups. In addition to having data redundancy, metadata is also striped across several drives.
I have a cluster with several RAID 6 volumes in it, each consisting of 12 drives. As long as no more than 2 drives fail in the same RAID volume, the data can be recovered.
storcli for most RAID operations. The below is an example where drive #7 in the first enclosure, on the first RAID controller has failed:
# Turn on the locator light to make sure the right drive is replaced
storcli /c0/e0/s6 start locate
# This is where I pull the bad drive and replace it with a good one
# Sometimes it needs to be inserted into the RAID, such as if you want to bring in a different available drive.
storcli /c0/e0/s6 insert dg=2 array=0 row=3
# Now that the drive is registered as part of the ARRAY, you can start the rebuild
storcli /c0/e0/s6 start rebuild
# Check up on the rebuild status
storcli /c0/e0/s6 show rebuild
# Turn of the locator light. We don't need that anymore
storcli /c0/e0/s6 stop locate