Call us gearheads, but at TechMikeNY, we’re fascinated by all of the hardware and parts of an enterprise server. We often field questions from our customers on cable compatibility, specifically the many variables with Dell backplane cables.
To better inform, we thought it would be helpful to describe the nuances of these backplane cables. Call it Server Anatomy 101: Know Your Backplane Cables!
Backplane Cable Basics
Backplanes for today’s modern rack servers are almost exclusively used to house the hot-swappable drives of the machine. (If you want to get technical, it’s a “passive backplane,” which means that circuitry to manage the communications between the slots is contained off the backplane. You can read an excellent history of backplanes here.)
Unlike standardized internal ports and connectors, like SATA, SAS, and PCIe, the correct backplane cable can vary significantly between the model server. For example, (how many bays), the server generation (Dell 12th Gen vs. Dell 13th Gen), if you connect to a mini-RAID controller, a PCIe RAID controller, or the native RAID controller built into the system board, can all be factors.
This post will give some examples of the varieties of SAS backplane cables.
| TROUBLESHOOTING TIP: The SAS backplane – even if you are utilizing the native controller – must be connected. That may sound obvious, but you would be surprised how many times a missed troubleshooting step is confirming that the SAS backplane cables are securely in place. The server will not boot if the SAS backplane is not connected, and in the BIOS or iDRAC menu, an error, “Backplane X connector X is not connected,” will show. |
Difference Between 12th and 13th Gen Dell Rack Server Backplane Cables
The 12th and 13th generation SAS backplane connectors are different – specifically, the 12th Gen takes cable SFF-8087, and the 13th Gen (and 14th Gen) takes SFF-8643.
Additionally, the connectors on the mini-RAID cards are exclusive to those controllers, and the connectors differ from the Dell 12th and 13th & 14th Gen servers.
One last variable with SAS Backplane cables is the consideration of how many active drive bays the server will have. Any Dell server with more than four hard drives will have two SAS backplane cables labeled “BP SAS A” and “BP SAS B.”
One last note on split backplane cables: while any server housing over four active drives will require the second cable & connector, that additional connector is all that is needed for however many drives. In other words, whether it’s six drives, or twenty-six drives – it will be the same split cable & connector.
| WE’RE HERE FOR YOU! If you order a standalone RAID controller from TechMikeNY, a representative usually will reach out to confirm compatibility with the server you want to install it in. Additionally, we’ll provide whatever cabling you need – depending on our stock – free of charge. That’s the TechMikeNY connection! |
Final Thoughts
While the nuance of cable compatibility with Dell SAS backplanes can seem daunting at first, some basic questions can help you determine what cable you need:
- What is the Generation of the Dell Server? 12th Gen takes different SAS backplane cables than 13th and 14th Gen.
- How many bays will have active drives installed? If it is over 4, you need to make sure you have the 2-connector cable.
- What type of RAID controller is connected? A Mini or a PCIe? The Mini controllers have proprietary connectors/cables that will ONLY work with a particular generation of Dell server. For PCIe controllers, cables are cross-compatible between Dell and 3rd party PCIe controllers, but the controllers themselves are not compatible across Dell server generations; a 12th Gen controller would not be compatible with a 13th or 14th Gen Dell server. (Just check before you buy.)
For example, the following are all SFF-8643, but the specific cable you'll need will depend on the specific server / configuration. So breaking down compatibility would look like:
Dell Part Number: 08Y2C8
Chassis: R640 (14th Gen)
Bays: 10-bay
Purpose/Type: SAS cable for mini RAID controllers
Dell Part Number: 0K9TVP (Buy from TechMikeNY)
Chassis: R630 (13th Gen)
Bays: 10-bay
Purpose/Type: NVMe expander SAS cable for 4x NVMe drives (SFF-8643)
Dell Part Number: 0129TR
Chassis: R740 (14th Gen)
Bays: 16-bay
Purpose/Type: SAS cable for PCIe RAID controllers
Dell Part Number: 0JTKYP
Chassis: R740xd (14th Gen)
Bays: 24-bay
Purpose/Type: SAS cable for mini RAID controllers (SFF-8643)
Lastly, it bears reminding that the integrated RAID controller in a Dell server can only configure a maximum of four drives – SATA ONLY – in RAID.
Have more questions? Drop us a line at info@techmikeny.com. We do this all day and love hearing from our customers!