Ok, so I think I've already decided the final configuration to use. I wanted to share it with us before start to collect the items, so you can give me your oppinions (I have to say that people on this forum are really amazing, thanks!).
- Velociraptor 300GB 10k rpm under the optical drive, as boot drive.
- RocketRaid 4320 (PCIe x8, 2 SFF-8087, 1.2Ghz, 256MB, online capacity expansion)
- Sans Digital TowerRaid TR4X (4 bays, SFF-8088 interface to host, Mac Pro like design)
- SFF-8087 to SFF-8088 converter, to make one of the internal Mini-SAS connectors on the RAID card to external.
- SFF-8087 to SFF-8087 cable with enough length to connect the RAID card to the 4 internal bays of the Mac Pro.
- SFF-8087 to 4 SATA cable to connect to the iPass connector where the original Apple's cable was connected. This way, I avoid using the ODD_SATA connectors on the motherboard, which gives problems when using with Bootcamp. One of the SATA connectors will be plugged to the Velociraptor for booting purposes. The other 3 are free for expansion (maybe one more drive under the optical drive, or a Blue-Ray unit with SATA interface... things like that).
- 8 Western Digital WD20EADS 2TB (I already have 2 of them, so 6 more). 4 of them on the internal bays, and the other 4 on the enclosure. Both arrays on RAID5 with spare disk. Maybe I will buy just up to 6 drives, mount them on groups of 3, and leave the empty bays (internal & external) for expansion later, if I can reach all with my budget. Because the RockerRaid has the online capacity expansion feature, I should be able to add the 4th disks on each array at any moment without removing data. What I'm not sure is if I will be able to activate the spare disk then, because with an initial configuration of 3 disks, I don't think will be able to activate it at the beginning.
This will give me ~6 TB of data capacity, and ~6 TB for backups, which should be enough for some years
When I need to increase the capacity in the future, 3 TB disks could have appeared, so I probably wouldn't have to buy a SAS expander plus extra enclosures.
How does this sound? Thanks!