Use the LSI sas2ircu utility to display the status of the RAID volume and its associated drives.
Refer to the SAS2 Integrated RAID Solution User Guide for more information about displaying and interpreting device status using the sas2ircu utility.
Of course you can configure RAID if you want, but the preferred best practice for Solaris 10 is to use ZFS as your boot filesystem, and give it 2 disks to create the rpool. ZFS kind of requires that you give it a pair of disks so that it can manage the mirroring. This allows it to be able to fix any disk errors within the ZFS filesystem.
In other words, if you want to use ZFS (which you should, as it is the default for Solaris 11, and you might as well get used to it, and it has a number of cool features, specifically snap and clone which makes Live Upgrade really easy to do), then simply present a pair of disks to ZFS. Don't mirror at the RAID level.