I just ran into this when trying to backup a few HDD images, and running a few VMS, i bought 2, 120GB SSD for caching but I looks I'll need 200GB-500GB to not run into any issues.
I setup the cache because the VMs HDD access was sluggish.
I need 2 SSDs for duplication.
Question, i don't really want to waste those SSDs or money, is it possible to pool the 2, 120gb SSDs and buy 2 more 120gb SSDs and pool those, so i can a 240gb 2x duplication SSD cache? So, (120+120) + (120+120)?