Recently I plugged in an old box we got a while ago that used to crash weirdly during boot and to my surprise, everything works now. 'bioctl mfi0' gave me further surprises, as it claimed there was a four disk RAID17 volume.
It turns out megaraids give us SNIA DDF raid levels, which include exotic things like RAID 1E, 5E, and 5EE. This volume happens to be a RAID 1E. mfi/mfii just copy this into bv_level when describing the volume to userland, so these values get treated as simple raid level numbers by bioctl: #define MFI_DDF_PRL_RAID1E 0x11 #define MFI_DDF_PRL_RAID5E 0x15 #define MFI_DDF_PRL_RAID5EE 0x25 I don't think we'd gain much by teaching bioctl to understand these, so should mfi/mfii map them to 1, 5 and 5 respectively?
