As previously mentioned, I relied on Disk Utility to handle my configuration of the Thunderbolt Duo, which enabled me to test both the full range of RAID block sizes and an additional configuration mode, concatenation. However, altering the RAID block size produced no discernable difference in the outcome, aside from minor variability that can otherwise be explained as normal run-to-run randomness:

WD Thunderbolt Duo Benchmark Results
Configuration mode AJA Write (MBytes/sec) AJA Read (MBytes/sec)
RAID 0 (16KB) 240.1 241.6
RAID 0 (32KB default) 239.3 241.5
RAID 0 (64KB) 239.6 241.5
RAID 0 (128KB) 239.5 241.1
RAID 0 (256KB) 240.4 241.4
RAID 1 (16KB) 120.0 122.4
(RAID 1 (32KB default) 119.8 121.5
RAID 1 (64KB) 119.1 122.5
(RAID 1 (128KB) 118.4 122.6
RAID 1 (256KB) 120.6 121.9
Concatenated 123.0 123.4
JBOD (A) 123.3 122.8
JBOD (B) 122.5 122.6

Not surprisingly, the RAID 0 striped results were roughly twice as fast than those either accessing a single drive at a time (JBOD and concatenated) or both drives simultaneously but in a mirrored fashion (RAID 1). Note that unlike with an elementary file copy test to or from another HDD or SSD, where the interface bandwidth limitations of the other drive might actually be the performance bottleneck, AJA System Test (like Iometer) generates data on-the-fly out of RAM.

Even after length and heavy access, and in spite of the Thunderbolt Duo's fanless design, both drives in the enclosure remained reasonably cool:

And the Thunderbolt Duo is also completely silent, save for the scant sounds of the drives themselves (further muffled by the enclosure surrounding them).

System and benchmark specifics GoFlex Desk results
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  • name99 - Monday, May 14, 2012 - link

    "Given that the PCI Express channel of the Thunderbolt interface delivers 10 Gbps of peak bandwidth in either direction, I next decided to see what would happen if I tethered the Seagate and WD drives together."

    You can do even better than this. You should have been able, in Disk Utility, to create a striped drive consisting of the two WD drives and the Seagate drive. This would be gated by the speed of the slowest drive, so should give you around 360MB/s read and write speeds.

    Disk Utility is not perfect, and god knows I've sent Apple long lists of ways it can be improved; but it is pretty awesome for basic things like creating either striped arrays or large concatenated arrays.
  • bdipert - Monday, May 14, 2012 - link

    Dear name99, that's a great idea. I'm traveling at the moment but will give it a shot when I get back in front of the Mac mini. I agree with you that it conceptually should work, and will be performance-gated by the drives in the Thunderbolt Duo.
  • Torrijos - Monday, May 14, 2012 - link

    You talked a bit about the impact of running a soft-RAID device being negligible, it would be nice to know the impact on the OS when pushing those mass storage devices to the limit.

    I've bought an USB3 extension card for my mac and while transfer speed are great, OS responsiveness takes a hit every time a big transfer occurs (TM backups are a pain).

    A formal test of the impact of USB 3, ThunderBolt would be nice.
  • repoman27 - Monday, May 14, 2012 - link

    Have you watched Activity Monitor during a TM backup to see what's being stressed? I usually associate the performance drop during TM backups with the crazy amount of small random reads that need to be performed on the system volume while you're still trying to use it.
  • Draconian - Monday, May 14, 2012 - link

    So basically, if you're really concerned about performance, an SSD using an old 3 Gbps connection will read and write twice as fast as a HDD using a Thunderbolt connection?

    I would be interested in knowing what the results would be with a HDD using an eSATA connection. And of course USB 3.0.
  • jabber - Monday, May 14, 2012 - link

    ......companies selling 7N Thunderbolt cables that cost them $3 to make but selling them to audiophiles for $3000 a go.
  • Glindon - Monday, May 14, 2012 - link

    Each connector of the thunderbolt cable has a small chip, which is why the cable costs so much. It's not just a $50 cable. iFixit has done a tear down of the cable if you want to check it out.
  • repoman27 - Monday, May 14, 2012 - link

    There are quite a few factors which make Thunderbolt cables expensive, being an active design is just one of them. If you ignore the bit about Thunderbolt being intended for iOS devices, the following blog post reveals quite a few details:

    http://www.patentlyapple.com/patently-apple/2012/0...

    I think the snake oil salesmen that prey on the audiophiles will avoid Thunderbolt for some time, specifically because it is an expensive to manufacture, high bandwidth cable that can't be made for $3. A 2.0 m copper pipe that can carry 20 Gbps, full-duplex, plus bus power and out-of-band signaling just doesn't exist yet in the sub $20 realm.
  • quiksilvr - Monday, May 14, 2012 - link

    You pay an arm and a fucking leg for these things and they don't even have the god damn decency to give you the wire?
  • CalaverasGrande - Monday, May 14, 2012 - link

    Just like on the MAc centric forums, people can not look past their narrow usage scenario to accommodate other perspectives.
    I work at a TV station, but have a background in audio production. In most prosumer studios, and quite a few mid level studios, firewire is the connection of choice for audio interface (soundcard). The high end audio interfaces have until recently all been either a PCIe card or Firewire. Add to the pile firewire based DSP such as the UAD-2 and firewire disk arrays used to insure fault tolerant and fast nearline storage.
    In video production we really don't use 1394 anymore. But there are still some old boxes in use that have the mini connector. Often they get pressed into use as a transcoder or layback machine for formats we dont use natively anymore. We are all on Sony XDcam disk, which I would love to see as a consumer format!
    I personally can't wait to see wider adoption of thunderbolt. I plan on upgrading to a T-bolt equipped mac after the next refresh of the MBP line.

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