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_nmon──4=Top-by-RAM-use───Host=aix1 Refresh=2 secs───15:09.41──────────────────────────┐

│ 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 don’t 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.

Tags:  aix nmon adapter iscsi i/o iscsi0 stats disk