O&O Defrag supports all hardware components that are supported by Windows. Please note the software requirements of the corresponding manufacturer.
As a rule: if you can access your hardware with Windows as you would a normal Windows partition, and this partition is formatted using a supported file system, this hardware can be defragmented. Removable drives such as streamers or CD-RWs are exceptions, since defragmenting them might not be useful. You can also set network drives as target for defragmentation.
RAID
Striped-, Mirrored- and RAID5-Volumes: The advantage of these drive types lies in their superior speed, which on the one side facilitates accessing and storing processes, and on the other hand offer a higher degree of data security.
O&O Defrag supports all known RAID systems. According to many hardware manufacturers, defragmenting RAID systems is especially important: as their files are spread over several hard disks, their fragmentation level is likely to be very high.