Note: Enabling Device Multipathing requires a reboot.
First, In order to enable Multipathing on OS level, Check Multi Path Utility package is installed.
If Not, You need to install it.
# pkg install system/storage/multipath-utilities
Enable Multipathing
Click Here to Continue : Few Steps to use EMC - SAN (LUNs) in Oracle Solaris - Part 03 Creating Pools