The manual says the system support JBOD+RAID1. JBOD will perform slower than RAID 0 since the HDDs store data contiguously rather than use striping. Other than that, the differences (from a user perspective) should be similar.
Again, I haven't personally used this configuration, so I can't comment on the functionality.
I configured a RAID1 and ended up with 2 volumes, each of 2TB.
I reconfigured as RAID1+JBOD and ended up with a 2TB RAID1 volume and a 4TB JBOD volume.
Currently running as a RAID5 6TB volume, but the performance is woeful compared to the RAID1.
I'd love to get a Single 4TB RAID1+RAID0 for best performance, or as second best a 4TB RAID1+JBOD.
I don't like my chances though.
