Did you do an upgrade from 4.1 or did you install ESXi 5 from scratch?

I heard several reports about PERC 6 perfectly working with ESXi 5, but we're unable to reproduce these results. We tried several different boards with older and newer firmware.

ESXi 4.0 and 4.1 → no Problem.

ESXi 5 → no local storage found.

I just wanted to confirm your problem (as it is mine). I have a whitebox ESXi 5 machine (fresh install, no upgrade) where the Perc 6/i fails to function correctly (visible via lspci, but the megaraid_sas module picks up 0 cards). Under Linux (Knoppix) on the same hardware the card works better (VDs present) but not perfectly since MegaCli refuses to see the card.

I previously suspected this was a motherboard (Supermicro X9SCA-F) + Perc 6i combination issue as the same card works beautifully in two other motherboards with ESXi 5 (ASUS M2NPV-VM, Gigabyte GA-M720-US3), but now I'm not so sure anymore. Would it be possible for you to verify / disprove that the combination of Perc 6i + "genuine" Dell machine and ESXi 5 exhibits the same problem?

We have the very same combination. Install ESXi 4.1 and it works. Try ESXi 5 and you get "claimed 0 device".

At the moment I have no Dell with PERC6 to play with.

Ok, that kind of settles it. I'll file a bug report with Supermicro (not that I believe they consider the Perc 6/i a viable supported card for this motherboard, but it can't hurt, can it?).

I updated a couple of servers from 4.1U1 to 5U1. One was a Dell R300 with PERC 6/i - no problem there!

Another has Supermicro X9SCM-F with PERC 6/i - couldn't find any storage device. So I had to leave it running ESXi 4.1U1.

I have no explanation.

Well, neither have I but it's definitely BIOS version-related. A workaround was presented by user dru2 in this thread: http://www.vm-help.com/forum/viewtopic.php?f=25&t=3601 , I flashed my X9SCA-F with the oldest BIOS version I could find (0630) and voilà, the storage turned up.