The Pegasus: Software

The Pegasus ships fully functional from the factory, but you'll need to do a couple of things to your Mac before the first Thunderbolt device on the market will just work. First, the Pegasus (or any TB device) will only work on a 2011 MacBook Pro or 2011 iMac as those are the only two systems on the market today with an integrated Thunderbolt controller. Apple is widely expected to introduce a new Mac Pro and maybe even a new MacBook Air with Thunderbolt support, but for now you need a 2011 MBP or iMac.

If you have one of those two systems you'll need two software updates. The first is the Mac Thunderbolt Firmware Update and the second is Mac OS X 10.6.8 (or later, Lion is supported). With both software updates installed, simply plug in a Thunderbolt cable and you'll be greeted with a Promise RAID icon on your desktop.

The bundled Promise Utility gives you full control over the Pegasus including reporting on drive/array health:

The major functions of the Promise Utility are pretty self explanatory. The Dashboard is the home screen of the application, it gives you a quick look at the current status of your drives/arrays (e.g. green for good, yellow for caution, red for major issue):

By default the Pegasus ships in a RAID-5 configuration with either 4 or 6 drives depending on whether you bought an R4 or R6 model. The RAID-5 array is configured with a 128KB stripe size and 512-byte sector size. This generally offers the best balance of redundancy and performance for most users, however if you'd like to delete it and start anew you can.

The wizard gives you one click array creation if you don't want to deal with adjusting things like stripe and sector sizes. There are varying levels of advanced array creation, or you can always go full manual.

You can choose any combination of drives in the Pegasus to be included in a disk array. From there you can partition the aforementioned disk array into any valid RAID array(s) you'd like. For example, you can choose to include all 6 drives in an array and from there create a 2TB RAID-0 and use the remaining space as a 6.4TB RAID-5. Alternatively, you can use five drives in an array and use one as a hot spare. Finally you can choose to only use some of the drives in an array and leave the remaining drives in pass-through mode, accessible outside of any RAID arrays.

Any drives you don't include in the drive array can be set as spares.

The table below shows you the options you have when creating a custom drive array on the Pegasus (I've highlighted the defaults):

Promise Pegasus Array Creation Options
Item Options
Stripe 64KB, 128KB, 256KB, 512KB, 1MB
Sector 512 Bytes, 1KB, 2KB, 4KB
Read Policy ReadCache, ReadAhead, No Cache
Write Policy WriteThru, WriteBack

All major configuration changes require that you type the word "confirm" before proceeding, a nice way to ensure you don't accidentally delete something.

The Promise Utility reports on both array and drive level events. It'll tell you basic things like whether or not your current array is healthy or down a drive. At the drive level you do get basic SMART reporting including temperature and health status. You also have the option of dumping an advanced SMART log to a text file which includes the drive vendor specific SMART attributes and their current, worst and threshold values:

In the utility's physical drive list you can locate any drive in the Pegasus array. Hitting the locate button will cause the corresponding identify LED to blink on the Pegasus.

Like any other array under OS X, you do have to manually eject any volumes before unplugging the Thunderbolt cable or powering down the Pegasus. Failing to do so will give you this all-too-familiar error:

The Thunderbolt Cable The Pegasus: Quirks


View All Comments

  • Spazweasel - Friday, July 08, 2011 - link

    $50 too much for a cable? Psshh. Children these days don't remember $75-100 SCSI-3 and UltraSCSI cables. These things are expensive for good reason.

    You want the highest performance, you pay to play. That's always been the case.
  • tzhu07 - Friday, July 08, 2011 - link

    The phrase, "you get what you pay for" is generally true as a rule of thumb, but in the computer and consumer electronics industry, that has for the most part been untrue.

    Case in point: The high price of Monster cables having no performance advantage over the same type of cables one can find on newegg at a much lower price.

    Apple just has this technology cornered....for now.
  • tzhu07 - Friday, July 08, 2011 - link

    Well, I should say untrue in the computer and consumer electronics cable market. Reply
  • darwinosx - Friday, July 08, 2011 - link

    The technology is Intel's not Apples. Intel determines the licensing fees. Reply
  • Samus - Friday, July 08, 2011 - link

    Yes, but like SCSI, Apple was its only mainstream delivery vehicle. Back in the 80's and 90's, SCSI interfaces were reserved for servers, ultra high end workstations, and Apple computers. They always push the bleeding edge, which is possibly the only thing I respect about Apple. Reply
  • Justin Case - Saturday, July 09, 2011 - link

    This has nothing to do with "pushing the bleeding edge". This has to do with giving Apple an "excuse" to remove USB ports from their iToys, thus locking out 3rd party accessory manufacturers (Thunderbolt is far too expensive to be competitive, unless you have a special deal like Apple has with Intel).

    The Mac hasn't been Apple's main focus for a long time; it's all about iOS and its ecosystem, now.
  • haley2011 - Sunday, July 10, 2011 - link

    ok Reply
  • MySchizoBuddy - Sunday, July 10, 2011 - link

    doesn't the article specifically say that thunderbolt is free to license.
    Isn't Promise Pegasus a 3rd part manufacturer. Do you have any source claiming that Promise has a special deal with Apple.
    Sony has thunderbolt ports in it's laptop as well.
  • Focher - Sunday, July 10, 2011 - link

    Besides that you give away your bias of anything from Apple, TB isn't an Apple technology. It's an Intel one. What I find ironic is the USB versus TB arguments. First, it's a false choice. Even Apple has offered both FireWire and USB ports for years on their machines. It's only recently that FireWire has started to be removed from models. There's no current indication that USB will be dropped by Apple. Second, in specific regards to USB 3.0 I don't see the argument versus TB device availability. Neither have much market penetration yet, so only time will tell how each of them will do - and both could do fine or both could fail. Reply
  • MobiusStrip - Tuesday, July 12, 2011 - link

    iOS devices are toys, but they already lack USB ports. They don't have any proper developer- or user-accessible I/O, so you think Apple's going to put Thunderbolt ports on them?

    NO. Apple has created a whole line of mobile devices that are ironically isolated from the world around them.

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