JBOD Storage Configuration on new Build Ideas and Assistance

Question

I'm new to storage, and I'm building out a new server for my client. I am more of a networking professional (CCNP, JNICP, Palo Alto), so this is brand new to me as I try to learn this. I've been scouring the web, but no luck getting the information I need.

I'm building a server with the following specifications:

Intel Xeon E5-2560 v3 x 2
512 GB TB LR-DIMM DDR4 EEC RAM
Norco RPC-4224U Server Chasis
4 TB SAS Seagate HDDs x 24
ASUS Z10PE-16/4L Motherboard

I'm in the middle of now figuring how to connect the 24 physical hard drives to the motherboard. I'm confused a little bit about RAID controllers, RAID cards, and SAS Expanders. What's the difference? And which one do I use?

I am just only presenting the hard drives to the operating system (ESXi) vanilla, meaning as 4 TB drives for 24 QTY.

I'm on a limited budget, and I don't know if the Areca 1883IX-24 (which is very expensive), Adaptec 2274900-R 72405, which is much cheaper, or a SAS Expander will work?

I am leaning towards Adaptec 2274900-R 72405 but I don't know if it will work. Any help and guidance would be appreciated.

If anyone else knows or can recommend any other piece of hardware for this setup to get the 24 Hard Drives connected at a much cheaper price, that'll be great!

Answer 1

I'm familiar with that chassis so I'll take a stab at this one. (I own the RPC-4220)

I am just only presenting the hard drives to the operating system (ESXi) vanilla, meaning as 4 TB drives for 24 QTY.

When using this method, a RAID controller is not required for implementation. A HBA (Host Bus Adapter) will suffice and they are significantly cheaper.

Since the chassis has six SFF-8087 connectors, finding a HBA with enough available connectors will be a bit of a challenge, though not impossible and more ports equals more cost. This is where an expander comes in. Most expanders are proprietary to the chassis they are made for; however, there are a few DIY types out there. An expander functions as a high density port multiplier. In my implementation, I use a 24-port expander made by Intel (RES2SV240). I am aware of one that LSI also makes that supports even more drives; however it costs as much as a high end RAID controller.

Speaking with components I am familiar with, here goes…

Although the specifications state it support 24 ports (6 x SFF-8087 connectors), four (1 x SFF-8087 connector) are used for the uplink connection to the RAID controller/HBA so you can only effectively connect up to 20 SAS/SATA devices (5 x SFF-8087 connectors). Most expanders (including the one I mentioned can daisy-chain) though you must consider throughput bottlenecking when doing so. In my implementation I have single SFF-8087 port RAID controller (Adaptec 6445 2270200-R) connected to the expander (Intel RES2SV240), which in turn, connects to the five SFF-8087 connectors in my chassis.

Based on your drive quantity and the limitations of the expander in my example, you would require two expanders. You could either daisy-chain the expanders or what I would recommend, use a two port HBA/RAID controller and split the drives evenly across isolated expanders.

All this being said I would still recommend you use a fully functioning, quality RAID controller. Doing so removes a very large portion of the storage subsystem functions (such as calculating parity for RAID 5/6) from the server’s main CPU, it’s not a lot, but every clock cycle counts yes? Since you are obviously building a virtual machine host, you want to dedicate as much of the CPU to that function. If you do go the route of a RAID controller, do NOT forget the backup battery/flash module for whichever you get.

References:

https://en.wikipedia.org/wiki/Port_multiplier

https://en.wikipedia.org/wiki/Host_adapter