When I run  powercf -q on my Solaris machine, what changes does this command do on the EMC storage, or on  Solaris file system?From manual page: DESCRIPTION During system boot on Solaris  hosts,  the  powercf  utility configures  PowerPath  devices by scanning the HBAs for both single-ported and multiported storage  system  logical  dev- ices.  (A multiported logical device shows up on two or more HBAs with the same storage system subsystem/device identity. The  identity  comes  from the serial number for the logical device.) For each storage system logical device found in the scan  of  the HBAs, powercf creates a corresponding emcpower device entry in the emcp.conf file, and it saves  a  primary path and an alternate primary path to that device.
EMC storage + powercf command + powerpath
solaris;storage;cluster
It doesn't make any changes on the EMC storage.  It only scans the fibre channel bus to see what world-wide names are visible through each local port.  If it sees the same WWN through multiple ports, then it sets that storage device up for multipath I/O.Changes are made to emcp.conf in /kernel/drv, and those changes in turn effect how device paths are created under /devices and/or /dev.  If you're on a Solaris system with a zfs root, you can install fresh, snapshot the system, then install PowerPath, run powercf -q, and do a zfs diff rpool/ROOT/solaris@snapshot rpool/ROOT/solaris to see exactly what changed in your root filesystem.If you don't have zfs root, you could always install a system, let it sit for 30 minutes, then run powercf -q, then use find / -mmin -30 to find files younger than 30 minutes.  