All 6718's are the exact same part number: 04N2737
They are all 17GB disks. Those two just appear as 8gb disks because they
are holding the raid striping.
Just go into SST and add them to the ASP and start using them.
3. Work with disk units
2. Work with disk configuration
4. Add units to ASPs and balance data
If you don't have option 4, try
2. Add units to ASPs
Turn off raid. First thing you'll notice is that 8GB disks magically
became 17 gb disks! Now, start raid again. Instead of the striping just
being on two drives it should be on 4 drives. So now your six 17gb drives
becomes four 12GB drives and two 17Gb drives. Perhaps your system started
out with fewer drives (that's why you have 2 drives in the stripe) and
drives were added later.
Once you have the raid looking better, then go into SST and add the "new"
drives to the asp and balance the data.
After running for a week you may want to look at rebalancing based on
performance. That's a new thread...