Maximize data availability 

Use Solaris Volume Manager's mirroring feature to maintain multiple copies of your data. You can create a RAID 1 volume from unused slices in preparation for data, or you can mirror an existing file system, including root (/) and /usr.

How to Create a RAID 1 Volume From Unused Slices

How to Create a RAID 1 Volume From a File System

Add data availability with minimum hardware cost 

Increase data availability with minimum of hardware by using Solaris Volume Manager's RAID 5 volumes. 

How to Create a RAID 5 Volume

Increase data availability for an existing RAID 1 or RAID 5 volume 

Increase data availability for a RAID 1 or a RAID 5 volume, by creating a hot spare pool then associate it with a mirror's submirrors, or a RAID 5 volume. 

Creating a Hot Spare Pool

Associating a Hot Spare Pool With Volumes

Increase file system availability after reboot 

Increase overall file system availability after reboot, by adding UFS logging (transactional volume) to the system. Logging a file system reduces the amount of time that the fsck command has to run when the system reboots.

About File System Logging