In order to get a single volume out of two raid controllers, you need to use software raid. I do not know of a single controller vendor that can handle raid controller spanning for single volumes.
While this is true for "MOST" controllers...it's not true for all....
My Ciprico RAIDcore controllers easily span arrays across multiple controllers. The RAID stack handles it natively, Windows has nothing to do with it. I have 4 controllers right now in my main server, each with 8 ports, and I can certainly have a single array that spans all 32 drives.
Next, windows software raid WILL NOT let you grow an array.
Yes and No. Windows software RAID will not let you grow a "RAID-5" array. You can certainly grow a simple striped or spanned array using diskpart.exe.
Plus any non-server os cannot handle raid 5 without considerable tweaking.
Sort of. XP (with hacked Server 2003 DLLs) handles RAID-5 just fine, and if you have a hardware RAID card, then of course it can handle it just fine. Vista has (yet) not been hacked to support the DLLs from Server 2008 so, no software RAID-5 there.
Even server os's can't handle raid 6.
Sure they can, if you have enough horsepower, the OS will happily do it. Linux does RAID-6 beautifully. Windows does lack there with no native RAID-6 support.
If you plan on snaking sata cables out the back and into 2 other norco cases then good luck. Very few have snaked cables out to 1 other norco case.
Been there done that.
All my drives sit outside the server chassis, in their own disk chassis' and the SATA cables snake out from the server chassis to the disk chassis'. No issues there. Been running rock solid like that for over 4 months (and I had the same setup before, ran flawlessly for over a year).
If i wanted to have 24 cards in RAID6, I couldnt do it with vista? Even if i purchase a controller that can handle RAID6? And I would have to purchase all 24 harddrives at the same time, and build the array because I wont be able to expand from 6 to 24 over time?
If you have a hardware RAID controller, whether 24 or 9 or 64 or whatever number of ports, Vista or XP or 2003 or 2008 will happily play with it. If you have the 32 bit versions of the OS you may run into the 2TB limit for volumes, but with a 64 bit OS, it will happily mount any earthly sized array.
No, you do not need to buy all 24 disks at the same time. That's the whole point of a hardware RAID controller, and OCE (Online Capacity Expansion). You can certainly expand over time.
I thought that the workaround is using a RAID controller and its hardware/software to build arrays that are RAID6, and to expand from 6 drives to 24 drives overtime. This isnt possible?
Absolutely correct, that's the whole point of a hardware controller.