Explanation/Reference:
Creating a ZFS Storage Pool with Cache Devices
You can create a storage pool with cache devices to cache storage pool data. For example:
# zpool create tank mirror c2t0d0 c2t1d0 c2t3d0 cache c2t5d0 c2t8d0
Note:
* Creating a Basic Storage Pool
The following command creates a new pool named tank that consists of the disks c1t0d0 and c1t1d0:
# zpool status tank
pool: tank
state: ONLINE
scrub: none requested
config:
NAME STATE READ WRITE CKSUM
tank ONLINE 0 0 0
mirror-0 ONLINE 0 0 0
c2t0d0 ONLINE 0 0 0
c2t1d0 ONLINE 0 0 0
c2t3d0 ONLINE 0 0 0
cache
c2t5d0 ONLINE 0 0 0
c2t8d0 ONLINE 0 0 0
errors: No known data errors
# zpool create tank c1t0d0 c1t1d0
These whole disks are found in the /dev/dsk directory and are labelled appropriately by ZFS to contain a single, large slice. Data is dynamically striped across both disks.
* Creating a Mirrored Storage Pool
To create a mirrored pool, use the mirror keyword, followed by any number of storage devices that will comprise the mirror. Multiple mirrors can be specified by repeating the mirror keyword on the command line. The following command creates a pool with two, two-way mirrors:
# zpool create tank mirror c1d0 c2d0 mirror c3d0 c4d0
Reference: Solaris ZFS Administration Guide, Creating a ZFS Storage Pool with Cache Devices