Multipathed I/O (MPxIO) enables I/O devices to be accessed through multiple host controller interfaces from a single instance of the I/O device.
Consider the following guidelines when using iSCSI multipathed (MPxIO) devices in Oracle Solaris:
Oracle Solaris iSCSI and MPxIO – MPxIO supports target port aggregation and availability in Oracle Solaris iSCSI configurations that configure multiple sessions per target (MS/T) on the iSCSI initiator.
Use IP network multipathing (IPMP) for aggregation and failover of two or more NICs.
A basic configuration for an iSCSI host is a server with two NICs that are dedicated to iSCSI traffic. The NICs are configured by using IPMP. Additional NICs are provided for non-iSCSI traffic to optimize performance.
Active multipathing can only be achieved by using the iSCSI MS/T feature in Oracle Solaris, and the failover and redundancy of an IPMP configuration.
If one NIC fails in an IPMP configuration, IPMP handles the failover. The MPxIO driver does not detect the failure. In a non-IPMP configuration, the MPxIO driver fails and offlines the path.
If one target port fails in an IPMP configuration, the MPxIO driver detects the failure and provides the failover. In a non-IPMP configuration, the MPxIO driver detects the failure and provides the failover.
For information about configuring multiple sessions per target, see How to Enable Multiple iSCSI Sessions for a Target. For information about configuring IPMP, see Chapter 3, Administering IPMP, in Administering TCP/IP Networks, IPMP, and IP Tunnels in Oracle Solaris 11.2 .
Oracle Solaris iSCSI, Fibre Channel (FC), and MPxIO – The MPxIO driver provides the following behavior in more complex iSCSI/FC configurations:
If you have dual iSCSI to FC bridges in an FC SAN, iSCSI presents target paths to MPxIO. MPxIO matches the unique SCSI per LU identifier, and if they are identical, presents one path to the iSCSI driver.
If you have a configuration that connects a target by using both iSCSI and FC, the MPxIO driver can provide different transports to the same device. In this configuration, MPxIO utilizes both paths.
If you are using iSCSI and FC with MPxIO, make sure that the MPxIO parameters in the /etc/driver/drv/fp.conf and the /driver/drv/iscsi.conf files match the MPxIO configuration that you want supported. For example, in fp.conf, you can determine whether MPxIO is enabled globally on the HBA or on a per-port basis.
Third-party hardware considerations – Find out if your third-party HBA is qualified to work with Oracle Solaris iSCSI and MPxIO.
If you are using a third-party HBA, you might need to ask the vendor for the symmetric-option information for the /driver/drv/scsi_vhci.conf file.