Support for K1 + K2 in the Same XenServer?

My understanding is that while there is no official nor OEM support for this, that it should in principle still work. Yet, when I do try this under XenServer 6.2, it only sees one of the GRIDs show up as recognized on a Dell R720. Is the slot order perhaps critical, are there specific firmware/BIOS/driver settings/versions needed, or am I attempting something that inherently just doesn’t work?

Our devs have quite a few of this kind of config kicking around as easy to swap between cards so surprised it’s not working… Both NViDIA and Citrix support it and it’s designed to do this…l just no OEM has chosen to certify a system and officially support it… Not sure why, maybe to simplify product matrix or lack of demand to date

Definitely working on xs 6.5 as saw this posted so not just us using dev code

Useful explanation by Andy currid

Thank you, Rachel, for your response. I called Citrix support on this a month or two ago and the tech stated that this was not a supported configuration, so I’m frankly not sure how I should proceed at this point. If there are internal logs or other indicators of where the issue may lie, I’d be happy to provide them. This R720 is still running XS 6.2, but I have just updated to the latest NVIDIA drivers, so I suppose I could give it another shot. It is correct that the order shouldn’t matter as to into which of the two x16 PCI slots the GRIDs are installed? The server is completely correctly speced for power, cooling, cabling, etc. and has a very recent BIOS.
Thanks much,

I can certainly try this again now that I have the latest drivers for XS 6.2 installed, but I would prefer not to have to update just yet to XS 6.5. So, is the recommendation to then update to XS 6.5, install the new related drivers, and then expect this to work? If the OEM (Dell) still doesn’t support the configuration, then it is to be assumed that Citrix won’t either, so if it comes down to a support issue it would appear I’m still going to be SOL.

I can experiment with all sorts of options, but they are all are rather time-consuming, so a recommended path with the best chance of a positive outcome would be appreciated.

Thanks much in advance,

One limitation can apparently be the space taken up for the base address registers (BARs), which if the server has a lot of embedded devices, can take up a lot of space and those for the GRIDs are pretty hefty. I’m going to try to trim things down some to see if that helps.

Otherwise, the good news is that since XenServer 6.5 runs with a 64-bit based OS, the issue with the 4 GB boundary is no longer an issue and that setting can be removed from the R720 BIOS configuration! :-) Thanks go to Paul Durrant of Citrix for pointing out the BAR limit issue.

Aha, resolved! I updated the driver on the XenServer 6.2 dom0 from 331.59 to 340.57 and apparently for whatever reason, both K1 and K2 GRID devices show up and work just fine. Was there a known issue with the earlier driver versions that prevented the mixed configuration?