IBM Midrange System DS4000 Series Hardware Manual page 473

Figure 7-90 Disk drive properties
In our example in Figure 7-91, we see:
A IBM 1818 Multi-Path Disk Device.
MPIO counts two paths. One path is Active/Optimized, and the other one is Standby.
– Active path on HBA port 4
– Standby path on HBA port 5 (port number does not refer the hardware port number of
the HBA)
Depending on the SAN/iSCSI topology, you might have more paths, but you usually have an
equal number of active and standby paths.
Figure 7-91 MPIO Path details
If the Access LUN is mapped to the server, an IBM Universal Xport SCSI Disk Device
appears in the Disk drives list. There is one for each DS5000 connected to the server.
Chapter 7. Advanced maintenance, troubleshooting, and diagnostics
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