Thanks for the replies, guys. Yeah, it's a crappy time to be buying disks, but with my luck being what it is that's is just par for the course.
🙄 Please bear with the following wall of text.
So let me answer the "what do you currently have" question first, as it actually involves two machines.
The Mac Pro is a 2008 dual-quad 2.8GHz w/ 32GB and an 8800GT running Lion. Current drives are one WDC Caviar Black 1TB (boot & apps) & three Maxtor DiamondMax 7200RPM 500GB in a software RAID0 (data/VMs). Backups go to a 2.5TB WDC Elements USB disk for Time Machine. This machine's daily workload consists of general office apps, photo retouching, light video editing, video trans-coding, and some gaming. I also maintain a VM test lab on it, with 2-4 VMs running most of the time. OS X & apps live on the boot volume; VMs and other data live on the RAID0. It doesn't set any speed records, but it performs perfectly well for my needs under its current usage.
The second machine is a 2005 iMac 2.1GHz G5 20" iSight w/ 2.5GB memory with Leopard. It serves primarily as my streaming media server and home NAS. Streaming targets are two

TV's, and 9 hosts share other data on it. It has an internal 500GB DMax 7200RPM (boot), a 1394a 500GB (nightly boot clone), a USB 1TB (iTunes), another USB 1TB (nightly iTunes clone), and a USB 1.5TB (TimeMachine). All external disks are single-disk enclosures. The Time Machine disk is dying (periodic Click-O-Doom), and I'm sitting at ~85% occupancy on the iTunes volume. I also think the NIC is dying as it can't handle more than one data stream without choking, whereas it used to have no trouble with two media streams and concurrent share access in its current configuration.
Now to answer the "what do you want to do" question.
I want to retire the iMac and consolidate down to the Mac Pro with an SSD boot/app volume and a 4TB data volume. Whether that's via 4x1TB RAID0 or 4x2TB RAID10 is immaterial to an extent, but at current prices I don't see 3TB disks in the equation right now. Backups will still go to slow external disks. I'm reasonably confident that this configuration, while not 'best of breed', will adequately support both current workloads on the Mac Pro alone. I really just need to "do something" before the iMac dies outright; and in consolidating machines, I want something at least slightly more robust than what I currently have.
The reason for wanting a 'real' RAID controller is to be able to rebuild the large array in the event of a disk failure. I had a software RAID10 with four 500GB disks at one point, and couldn't rebuild the array after replacing a dead spindle - Disk Utility can't cope with that unless you have the Apple RAID card (and screw that - sucker's way too expensive/problematic).
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I don't foresee needing
much in the way of online array transform capabilities, save for being able to rebuild the volume in the event of a spindle failure. And as long as it can do some kind of expansion, whether it's fast or slow isn't really a concern for me. If the MAXpower can't do a volume-intact expansion at all though, that would kill it as an option.
Why did I specify the Seagate Connies? Price (for being SAS), plus I have two SATA Connies in my desktop at work that I like.
🙂 But they only factor in for a SAS config. For SATA, the only thing that matters to me is that they not be DeskStars (bitten one too many times with these, tyvm
😡 ) and they must be 7200 RPM or better (so no Caviar Green).
I was unaware of the Areco products until today, if I'm honest. Thanks for pointing them out; I'll give them a look as well.
😎
Finally, building out the Mac Pro is not the only option on the table. I'm also considering leaving the Mac Pro as-is and building out a
Synology DS411+II (or similar) to replace the iMac. Another option under consideration is replacing the iMac with a Mac Mini and fresh external disks. So I'm still very much in the design & decision-making process, and the feedback is helping. Thanks!!
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