The drive setup looks fine if you backup regularly. SSD drives have such low latency you can put all the cache files there if you already have an SSD for the OS.
Why would you run RAID 0 for a backup? RAID 0 is for performance. For your backup you might want RAID 1 for redundancy but never, never RAID 0. More likely you could just use the two drives individually if you cannot afford a new larger drive.
You were misled about the reliability of enterprise drives. Being mechanically spinning devices, even enterprise drives can fail after less than one hour of operation. And that can (and has) occurred far more frequently than you were led to believe (although the failures have been few). The advantage of enterprise drives is that they are rated to run 24/7 constantly unlike desktop drives that are typically rated to be run no more than a few hours per day. Still, being mechanical, such drives can fail far sooner than you'd expect. And such a failure can occur (and has occured) even in the middle of backing up your media (which results in a complete and total disaster since the entire media file would be completely and irrecoverably lost in such a disk failure).
These are the exact reasons why I would not recommend a RAID 0 array as your sole backup drive. All backups should be done on single disks or (better) a RAID array that's configured to provide redundancy (remember, there is absolutely no redundancy at all whatsoever in RAID 0, and the data in a RAID 0 array is divided over two or more disks in that array, making it virtually impossible to recover in case of the failure of even one of the drives in the array). At least data can be recovered from a single non-RAID disk that has failed.
Eric - Thank you! I've never heard of putting the cache on the OS drive, but that would indeed save me some money and effort if it's not likely to degrade performance.
Bill and RJ - I apologize for wording it unclearly (plus a typo), but what I was trying to say was G: 2TB Backup of media/projects RAID 0 meaning G is a single 2TB drive acting as a dedicated backup of the media drive (which is a 2-disk RAID0). I am clear on the fact that RAID 0 has no redundancy, and doubles the risk of data loss.
RJ - I understand that even enterprise drives have a chance of failure, and perhaps in my circumstances the same chance as a regular drive, but I've been using these drives individually for a good while, have error and health checked them, so they're not duds. I would backup my media from the single drive where it now resides, setup the RAID 0, then restore the media to the new RAID 0 media drive so there'd be no chance (excluding lighting, bad luck or the wrath of the almighty) of losing everything mid-backup.
So, it appears the cheapest solution for me would be:
C: (120GB SSD) OS, Programs, Page. Cache, Previews
D+E: (2TB Spanned) Media, Projects
F: Single 2TB disk, backup of media/projects
Exports on D/E or F - it doesn't really matter to me. I don't mind waiting, and they generally go straight on the internet post-export.
Thank you for making that backup plan clearer. What you really meant was that the backup disk is a copy of what you've put on that RAID 0. That backup disk may be either internal or external; if external, eSATA would be fastest (for single external disks), followed by USB 3.0, then FW800. FW400 and USB 2.0 are slowest, largely because FW400 chips inside HDD enclosures are poorly implemented.
Yes, great! Thanks for that RJ.
The backup with be internal. I have a slow USB 2.0 drive for incrimental backups of only essential data.
Anyone else have (or heard of others having) the Cache/Previews on the OS drive?
Careful putting the Media Cache on the OS drive. Those files will chew through the space quickly and most people forget or don't know how to delete them. Also they build so fast that the SSD firmware wont be able to keep up with cleaning the garbage after you keep deleting them and the SSD drive will slow down. That is easy to fix on a media drive when you can just move the data off and run a clean command but not so easy on an OS drive. I would use a SSD media drive if you want a SSD for that.