Third-Party Device Configuration Considerations

Before you configure third-party devices for multipathing, be aware of the following:

• The device must support the REPORT_LUNS SCSI command, and SCSI-3 INQUIRY command VPD Device Identification Page (0x83).

• You will need the vendor ID (VID) and product ID (PID) of the device. You can obtain them by using the format command followed by the inquiry option on your system. See the format(1M) man page.

When multipathing is enabled, the multipath access still depends on a device specific scsi_vhci failover implementation accepting the device. The default way this occurs, automatically, is for the scsi_vhci code to call a probe function in each failover implementation, looking for the first probe result that indicates the device is supported.

A probe implementation determines support based on some combination of scsi_inquiry(9S) data. A device with INQUIRY data indicating T10 Target-Port-Group-Support (TPGS) compliance will use the standards-based TPGS failover implementation. For noncompliant devices, a failover implementation's probe will typically determine support based on VID/PID match against a private compiled-in table.

To override the probe process, the scsi_vhci.conf file supports a scsi-vhci-failover-override property. The value of scsi-vhci-failover-override can be used to establish support for a device not currently accepted by probe, override probe support, or disable multipath support for a device.