On SPARC S7-2L servers with a 12 drive backplane, all NVMe drive configuration, prtdiag shows incorrect NAC names for the NVMe drives in slots 3, 4, and 5 as below.
======================================== IO Devices =======================================
Slot + Bus Name + Model Max Speed Cur Speed
Status Type Path /Width /Width
-------------------------------------------------------------------------------------------
...
...
/SYS/MB/PCIE_SWITCH1 PCIE nvme-pciexclass,010802 8.0GT/x4 8.0GT/x4
/pci@300/pci@2/pci@0/pci@6/nvme@0
/SYS/MB/PCIE_SWITCH1 PCIE nvme-pciexclass,010802 8.0GT/x4 8.0GT/x4
/pci@300/pci@2/pci@0/pci@7/nvme@0
...
/SYS/MB/CMP1/IOS0 PCIX nvme-pciexclass,010802 8.0GT/x4 8.0GT/x4
/pci@302/pci@2/pci@0/pci@4/nvme@0
...
...
With correct NAC names for the NVMe drives in slots 3, 4, and 5, prtdiag output would show up as below:
======================================== IO Devices =======================================
Slot + Bus Name + Model Max Speed Cur Speed
Status Type Path /Width /Width
-------------------------------------------------------------------------------------------
...
...
/SYS/DBP/NVME4 PCIE nvme-pciexclass,010802 8.0GT/x4 8.0GT/x4
/pci@300/pci@2/pci@0/pci@6/nvme@0
/SYS/DBP/NVME3 PCIE nvme-pciexclass,010802 8.0GT/x4 8.0GT/x4
/pci@300/pci@2/pci@0/pci@7/nvme@0
/SYS/MB/PCIE5 PCIE nvme-pciexclass,010802 8.0GT/x4 8.0GT/x4
/pci@300/pci@2/pci@0/pci@15/nvme@0
...
...
Workaround: Use the format command or the diskinfo command to find the correct NAC names and associated device paths for the NVMe drives with this configuration. For example, type:
# diskinfo
D:devchassis-path c:occupant-compdev
----------------------------------- ------------------
/dev/chassis/SYS/DBP/NVME0/disk c14t1d0
/dev/chassis/SYS/DBP/NVME1/disk c15t1d0
/dev/chassis/SYS/DBP/NVME2/disk c16t1d0
/dev/chassis/SYS/DBP/NVME3/disk c7t1d0
/dev/chassis/SYS/DBP/NVME4/disk c6t1d0
/dev/chassis/SYS/DBP/NVME5/disk c13t1d0
/dev/chassis/SYS/DBP/NVME6/disk c9t1d0
/dev/chassis/SYS/DBP/NVME7/disk c11t1d0
/dev/chassis/SYS/DBP/NVME8/disk c12t1d0
/dev/chassis/SYS/DBP/NVME9/disk c3t1d0
/dev/chassis/SYS/DBP/NVME10/disk c4t1d0
/dev/chassis/SYS/DBP/NVME11/disk c5t1d0
...
# format
Searching for disks...done
AVAILABLE DISK SELECTIONS:
0. c14t1d0 <INTEL-SSDPE2ME016T4S-8DV1-1.46TB>
/pci@302/pci@2/pci@0/pci@17/pci@0/pci@4/nvme@0/disk@1
/dev/chassis/SYS/DBP/NVME0/disk
1. c15t1d0 <INTEL-SSDPE2ME016T4S-8DV1-1.46TB>
/pci@302/pci@2/pci@0/pci@17/pci@0/pci@5/nvme@0/disk@1
/dev/chassis/SYS/DBP/NVME1/disk
2. c16t1d0 <INTEL-SSDPE2ME016T4S-8DV1-1.46TB>
/pci@302/pci@2/pci@0/pci@17/pci@0/pci@6/nvme@0/disk@1
/dev/chassis/SYS/DBP/NVME2/disk
3. c7t1d0 <INTEL-SSDPE2ME016T4S-8DV1-1.46TB>
/pci@300/pci@2/pci@0/pci@7/nvme@0/disk@1
/dev/chassis/SYS/DBP/NVME3/disk
4. c6t1d0 <INTEL-SSDPE2ME016T4S-8DV1-1.46TB>
/pci@300/pci@2/pci@0/pci@6/nvme@0/disk@1
/dev/chassis/SYS/DBP/NVME4/disk
5. c13t1d0 <INTEL-SSDPE2ME016T4S-8DV1-1.46TB>
/pci@302/pci@2/pci@0/pci@4/nvme@0/disk@1
/dev/chassis/SYS/DBP/NVME5/disk
6. c9t1d0 <INTEL-SSDPE2ME016T4S-8DV1-1.46TB>
/pci@302/pci@1/pci@0/pci@13/pci@0/pci@4/nvme@0/disk@1
/dev/chassis/SYS/DBP/NVME6/disk
7. c11t1d0 <INTEL-SSDPE2ME016T4S-8DV1-1.46TB>
/pci@302/pci@1/pci@0/pci@13/pci@0/pci@5/nvme@0/disk@1
/dev/chassis/SYS/DBP/NVME7/disk
8. c12t1d0 <INTEL-SSDPE2ME016T4S-8DV1-1.46TB>
/pci@302/pci@1/pci@0/pci@13/pci@0/pci@6/nvme@0/disk@1
/dev/chassis/SYS/DBP/NVME8/disk
9. c3t1d0 <INTEL-SSDPE2ME016T4S-8DV1-1.46TB>
/pci@300/pci@1/pci@0/pci@11/pci@0/pci@4/nvme@0/disk@1
/dev/chassis/SYS/DBP/NVME9/disk
10. c4t1d0 <INTEL-SSDPE2ME016T4S-8DV1-1.46TB>
/pci@300/pci@1/pci@0/pci@11/pci@0/pci@5/nvme@0/disk@1
/dev/chassis/SYS/DBP/NVME10/disk
11. c5t1d0 <INTEL-SSDPE2ME016T4S-8DV1-1.46TB>
/pci@300/pci@1/pci@0/pci@11/pci@0/pci@6/nvme@0/disk@1
/dev/chassis/SYS/DBP/NVME11/disk
For additional information about drive errors, see S7-2L 12- and 24-Disk Backplane Systems Unable to Enumerate Disks (18712182).