If you have the AIX iSCSI Software Initiator (iscsi0) configured on your system, you may find that nmon reports some funny information under the Disk Adapter (a) and Disk I/O (d) screens, such as:

topas_nmon4=Top-by-RAM-useHost=aix1 Refresh=2 secs15:09.41

Disk-Adapter-I/O

Name %busy read write xfers Disks Adapter-Type

vscsi1 0.0 0.0 0.0 KB/s 0.0 4 Virtual SCSI Client A

vscsi0 0.0 0.0 0.0 KB/s 0.0 4 Virtual SCSI Client A

Adapter name "not available" returned by AIX API

vscsi3 0.0 0.0 0.0 KB/s 0.0 12 Virtual SCSI Client A

vscsi2 0.0 0.0 0.0 KB/s 0.0 12 Virtual SCSI Client A

TOTALS 5 adapters 0.0 0.0 KB/s 0.0 32 TOTAL(MB/s)=0.0

Disk-KBytes/second-(K=1024,M=1024*1024)

Disk Size Free Disk Disk Volume Disk

Name GB GB Paths Adapter Group Description

hdisk11 29 0 1 vscsi1 localscratchvg Virtual SCSI Disk Drive

hdisk1 50 20 1 vscsi1 rootvg Virtual SCSI Disk Drive

hdisk9 25 0 1 vscsi1 localscratchvg Virtual SCSI Disk Drive

hdisk3 50 34 1 vscsi1 datavg Virtual SCSI Disk Drive

hdisk2 50 34 1 vscsi0 datavg Virtual SCSI Disk Drive

hdisk8 25 0 1 vscsi0 localscratchvg Virtual SCSI Disk Drive

hdisk10 29 0 1 vscsi0 localscratchvg Virtual SCSI Disk Drive

hdisk0 50 20 1 vscsi0 rootvg Virtual SCSI Disk Drive

hdisk6 0 0 1 not available None MPIO NetApp iSCSI Disk

hdisk16 0 0 1 not available None MPIO NetApp iSCSI Disk

hdisk17 0 0 1 not available None MPIO NetApp iSCSI Disk

hdisk12 0 0 1 not available None MPIO NetApp iSCSI Disk

hdisk7 0 0 1 not available None MPIO NetApp iSCSI Disk

hdisk13 0 0 1 not available None MPIO NetApp iSCSI Disk

hdisk14 0 0 1 not available None MPIO NetApp iSCSI Disk

hdisk15 0 0 1 not available None MPIO NetApp iSCSI Disk

hdisk4 50 0 1 not available projvg MPIO NetApp iSCSI Disk

hdisk5 750 0 1 not available ipscratchvg MPIO NetApp iSCSI Disk

hdisk18 104 54 2 vscsi2 projectsvg Virtual SCSI Disk Drive

hdisk19 104 0 2 vscsi2 scratchvg Virtual SCSI Disk Drive

hdisk20 104 0 2 vscsi2 scratchvg Virtual SCSI Disk Drive

hdisk21 104 0 2 vscsi2 scratchvg Virtual SCSI Disk Drive

hdisk22 104 0 2 vscsi2 scratchvg Virtual SCSI Disk Drive

hdisk23 104 0 2 vscsi2 scratchvg Virtual SCSI Disk Drive

hdisk24 104 0 2 vscsi2 scratchvg Virtual SCSI Disk Drive

hdisk25 104 0 2 vscsi2 scratchvg Virtual SCSI Disk Drive

hdisk26 104 0 2 vscsi2 scratchvg Virtual SCSI Disk Drive

hdisk27 104 0 2 vscsi2 scratchvg Virtual SCSI Disk Drive

hdisk28 104 0 2 vscsi2 scratchvg Virtual SCSI Disk Drive

hdisk29 104 0 2 vscsi2 scratchvg Virtual SCSI Disk Drive

Totals(MB/s) Read=0.0 Write=0.0 Size(GB)=2354 Free(GB)=161

I dont know if there are any plans to fix this but I wanted to share this information in case anyone else encounters this issue. iSCSI is not all that popular on AIX systems (perhaps this is a good thing?), so it may not impact enough people to warrant a quick fix.