Yes, that's two strikes against me. But checksum caching won't help me with the initial backup, which takes 8+ hours.
Right now I'm leaning toward a 5-drive setup. One drive for the operating system, and the rest for the pool in a RAID 0+1 array, which, according to
http://www.z-a-recovery.com/art-raid.htm, will allow me to write twice as fast as with a single disk and which will tolerate disk failure fairly well. I guess it's a slight step up from Les's original suggestion.
One thing I'm not sure about with regard to RAID 0+1 arrays is how to recover from a disk failure. I understand that if you replace a drive in a RAID5, its contents are rebuilt using the parity on the other drives -- you can rebuild the array without powering down the machine (assuming you have hot-swappable drives). Is this possible for a RAID 0+1 configuration? If not, I guess there's no point in paying the premium for hot-swappable drives.
Thanks!
-Frank