Device Name (NAA) Truncated in ESXTOP
With the introduction of ESX(i) 4 and the included support of the SCSI-3 protocol comes a new way of displaying LUN information in the virtual environment called Network Naming Address Authority (NAA) identifiers. Each Fiber Channel or iSCSI LUN presented to an ESX(i) host has a unique SCSI NAA identifier. The NAA for each LUN is reported by the storage device to the ESX(i) host through an INQUERY which returns a VPD (Vital Product Data) response that includes the NAA identifier. Although the NAA is unique for each LUN, the NAA should remain consistent across all hosts for any particular LUN. The NAA identifier is generated by combining the word naa. with the 128-bit WWN of the LUN (ex. naa.600601607a401900d41ffaa5c17add11). In the preceding example, you can see the LUN is first identified by the word NAA; it is then followed by the WWN of the LUN. Because the WWN contains the IEEE assigned vendor OUI 006001 you can use a tool to find the LUN storage vendor (in this case “CLARIION”).
The length of the NAA presents a problem for the ESXTOP tool. ESXTOP is designed to show shorter device names (as seen in ESX 3.5 and earlier) when viewing “disk device” information. When you view disk device information through ESXTOP on an ESX(i) 4 host the NAA identifier is truncated which prevents the ability to identify a specific LUN (see truncated example below). ESXTOP contains an “L” option which allows users to specify the length of the Device field. By pressing the “L” key while in the “disk device” view and setting the value to 40, the NAA of each LUN become visible (see expanded example below).
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