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The SRCSASJV RAID controller has eight total SAS/SATA ports through two (x4 SAS port) SFF8088 Mini SAS 4i external connectors and two (x4 SAS Port) SFF8087 Mini SAS 4i internal connectors. The connectors can be configured through a SAS mux.The SAS mux is used to enable using either the internal or external connectors, but only allows eight total ports at a time. This can be two internal, one internal and one external, or two external ports.
The SRCSASJV RAID controller supports up to 240 SAS/SATA II devices via expanders. It has eight ports and can only support eight direct connected SAS/SATA II devices. So to control the 12 disks you want to use, there's no way to do that without using an expander.
To take that to another level, the SR2612UR is a server system, or more correctly a storage system. The SR2612UR has an expander that is connected to the RAID controller (server board or add-in) and connects to the backplane.
So in reality the SR2612UR was not meant to host 12 independant disks, but you could get around that going the way you are as the SRSASJV supports RAID level 0 and up to 128 arrays.
Thank you for this helpful answer. I'm not sure I understood everything so I still have questions.
My server was built by my retailer and is now running with 12 disks. So currently, I have a SR2612UR chassis + the SRCSASJV RAID controller + the active midplane + the 12 slots backplane. I understood I don't use SAS MUX because I just have one internal SFF8087 port used on my SRCSASJV RAID controller.
I don't like the multi RAID0 option so I won't use it. Also, I would like to SMART monitor my disks.
1 - When you talk about an expander; is my active midplane an expander ? Or is it my backplane ?
2 - Let's say I want to upgrade my SR2612UR storage system. I see here (Server Products RAID controller and module backplane compatibility list) that I can purchase another Intel controller. Please tell me there is at least one controller able to show independant disks, amongst the 28 controllers shown on the page !
3 - Is my active midplane compatible with a regular SAS card with just one SFF-8087 port ? These cards are refered to as compatible with only 4 disks. Will my expander work for 12 disks with this ? I'm not sure about this because I read somewhere that the SPF-8087 connector is not fully wired on Intel components.
Examples : PromiseTX4660 ; LSI 9660 ; Intel SASUC8I ; Supermicro AOC-USASLP-L8i
Even if my 3rd question is about other brands, I would appreciate an answser. In my company we have 20 Intel servers (which is quite a lot for our size) and we stay pretty faithful to Intel, until our servers do what we want them to do.
The SR2612UR active SAS midplane is designed around a PMC8388 24-port SAS expander. So the term midplane is a little blurred here. It's really just an expander device that enables SAS connectivity between any attached SAS host adapter and the 12 3.5-inch SAS/SATA hard disk drives located in the front of the enclosure.
For RAID controller compatibility with the SR2612UR, see the Intel® Server System SR2612UR Spares/Accessories List and Configuration Guide. But you'll find there that none of the controllers have more that eight ports. So to support the 12 disks you need the SR2612UR expander/backplane combination.
You cannot replace the expander (midplane) or backplane in the SR2612UR. See the SR2612UR Technical Product Specification for more information and system specifics.
Yes, the expander in the SR2612UR has four ports. The expander then "expands" to support 12 disks. You can think of expanders as a network switch in that regard.
Thank you very much for this valuable knowledge. This community forum is just perfect.
Of course, I already know I have to use my expander, for the reason you tackle (no SAS controller with more than 8 ports) and because the backplane connector is very specific.
On the Technical Product Specification you quote (page 42 of the PDF) the PCM8388-based expander/midplane has just one SFF8087 port. But it doesn't matter.
When you said "It's really just an expander device that enables SAS connectivity between any attached SAS host adapter", you answer to my question in my previous post because I wasn't sure a non-Intel SAS adapter was compatible with the expander.
I'm gonna buy a regular HBA SAS card (Supermicro AOC-USAS2-L8e), which will be connected with one SFF8087 port to the PCM8388-based expander/midplane. And of course, the expander/midplane will be connected to the backplane.
You're free to use your SR2612UR the way you wish, but we strongly recommend using devices that have been validated by Intel foir use with the SR2612UR. See the Tested Memory and Hardware List for more details.
Thje RAID controllers listed may not fit your specific requirements. If that's the case, we recommend you validate the controler you choose so you can be confident you will not have compatibility issues down the road.