Thanks for clearing that up Jim. What are you using for a backup drive? I've been using a 2gb Apple Time Capsule.
I use a 3TB Time Capsule for my wife's iMac, and a 2TB Time Capsule for our our laptops (two MacBook Airs).
The Pegasus will be permanently connected to my new iMac which is on order. The new iMac will not have a lot of capacity (just a 768 GB SSD)... so the 8TB Pegasus R4 (RAID 10) will add an additional 4TB of storage... which is more than I need. Currently my data set is about 1.5 TB. If I offload my iTunes library + all my iMovie camcorder videos to the Pegasus... everything else (including my Aperture library) will fit within the 768GB SSD.
I've been holding off on buying a new TC for the new iMac in hopes of them releasing a 4TB version. If not released by the time my new iMac arrives, I will get the 3TB TC since it will work fine given my 1.5 TB of data.
I *could* backup to a NAS array... but I prefer not to do so, since the only NAS officially supported by Time Machine is the TC. I do not want to deal with NAS firmware upgrades every time Apple decides to change something with TM. Backup should "just work" and not be a hobby to keep running... my data is too important for that. I could also use a direct connect drive... but I have a strong preference to keep my backup Time Capsules in a different part of the house, in a physically locked location. This prevents my iMac and its associated backup data from being stollen simultaneously if the local junkie does a smash and grab on my home office.
Of course... everything is also backed up to the cloud as well. Both iMacs and both MBAs... plus two other iMacs and two MBAs for my daughters who are college students living out of state or out of country. I use Crashplan+ to backup 8 computers... each every 15 minutes, all for $6/month. What a bargain!!!
I also have a pair of small cheap 1.5 TB Thunderbolt portable GoFlex drives that I use with CCC to create media backups (Aperture 3 library and camcorder videos) which I rotate between my home office and my corporate office whenever I make major changes to my libraries. This is just an extra belt + suspenders + jockstrap + condom approach to being extra safe with my irreplaceable data.
/Jim