Stripes are created only from slices, not other metadevices.
Do not use slices from disks with different disk geometry.
Use slices on the same controller but on different disks. Using stripes that are each on different controllers can increase the number of simultaneous reads and writes that can be performed.
Set up a stripe's interlace value to better match the I/O requests made by the system or applications.
Do not stripe partitions that are on a single disk. This practice eliminates simultaneous access and causes performance problems.
Use the same size disk components. Striping different size disk components results in unused disk space.
If you use slices of different sizes when striping, then disk capacity is limited to a multiple of the smallest.