Storage Controller Module
Through the shared SAS connection inside the chassis, the compute modules communicate with the storage controller modules. This enables the MFS5000SIs to utilize the assigned disks in the SAN. The storage control module also manages the SAN’s RAID teams and the disk virtualization that drives the storage pools using the management module’s modular server control application. An interposer card connects the storage controller module to the storage back plane sitting behind the hard disks. A hot-swappable storage controller module is required to run the 14 SAS drives in the MFSYS25’s SAN. For redundancy, a second storage controller module should be installed in case the first module fails during operation.
One additional function not included by default is the shared logical unit numbers (LUN) feature that enables two compute modules to share the same LUN. To enable this function, an activation code must be purchased and added to the system, using the modular server control’s Featured Activation UI.
On the front panel of the storage controller module, there are two additional interfaces. The first is a serial connection for accessing the storage module’s command line interface. It’s a port that Intel uses for low-level debugging and testing.
The second interface is an external SAS connector that, once activated, can be used to add an external SAS device (e.g. tape or disk) to the MFSYS25. I had some difficulty finding information about the use of the external SAS port, but with a little assistance from our Intel rep, I was able to get a document on how to connect the storage controller module to the Promise VTrak e610 and e310 storage devices. But while it’s a decent tutorial, a limitation of using the external SAS is that you can’t manage the newly added direct attached storage from the modular server control UI. Instead, you need to use whatever tool the DAS manufacturer offers.