Promise Pegasus R6 & Mac Thunderbolt Review
by Anand Lal Shimpi on July 8, 2011 2:01 AM ESTDisplayPort Passthrough
The Pegasus has two Thunderbolt ports. You can use the second port to daisy chain up to six Pegasus devices together, for up to 36 drives. With a single Pegasus in its default configuration able to hit over 5Gbps, you'd definitely run into bandwidth limitations with six of these things. But you could get by with two and not be limited by Thunderbolt.
There's another role that second Thunderbolt port can play: as a DisplayPort output. Remember both PCIe and DisplayPort are carried on a single Thunderbolt cable, the latter occupying half of the 40Gbps of total bandwidth available.
At the end of a Thunderbolt chain you can insert a miniDP display, currently the only option is the 27-inch LED Cinema Display but in theory other panels that accept a miniDP input could work as well.
I connected a 27-inch Cinema Display through the Pegasus without any problems. The Pegasus does have to be on for you to get video however, so if you ever have to shut down the Pegasus you do lose video to the Cinema Display.
Audio still works, so you'll see the Cinema Display as an audio device on your Mac:
The experience is pretty seamless overall.
I ran a quick test to see if I lost any bandwidth to the Pegasus with the 27-inch Cinema Display in the chain. I measured a slight performance drop (< 3%) in the best case scenario of four SF-2281 SSDs in a RAID-0 array on the Pegasus, but nothing substantial at all. Note that simply displaying an image at 60Hz on the 27-inch Cinema Display requires over 6.75Gbps of bandwidth (because of 8b/10b encoding), so a full Thunderbolt channel is necessary for DisplayPort (although admittedly it only needs to be unidirectional bandwidth).
| Thunderbolt PCIe + DP Bandwidth Test | ||||
| 2MB Sequential Write, QD16 | No DisplayPort Passthrough | 27-inch Cinema Display Connected | ||
| Promise Pegasus R6 (4 x SF-2281 SSDs, RAID-0) | 1002.7 MB/s | 988.2 MB/s | ||
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takumsawsherman - Saturday, July 9, 2011 - link
You mean like booting from a CD or USB flash drive and copying files to a very small, hideable storage container?Perfectly possible, and in fact I find myself doing this frequently (though copying the data in the other direction typically) when disinfecting PCs. I do this multiple times per week, removing data stealing trojans and rootkits.
Compare with Thunderbolt, where you will "sneak in with only a laptop and a cable and reboot and press T, and ZOMG yor datas are hax0red! Ha HA ha stupid Apple!!!111oneonewonwon"
Leaves obvious traces? Exactly what traces did the Boot CD leave?
Penti - Wednesday, July 13, 2011 - link
As you can password protect (which can be bypassed with physical access any way) the firmware it doesn't matter if it is Firewire/Thunderbolt-target or USB-stick/HDD that access and or copies the files or simply a CD that changes your password so you can just log in an access everything without any effort at all. If you don't have limits on the firmware/bios any way you can just set up whatever, and access anything without any effort, less so then using slow target disk mode, even through network boot is possible which might be on in a corporate/university environment any way.Just disable the good damn features you don't like, it don't make your computer safe but I'm sure it will quit you whining for nothing.
You will just access everything by running the system rescue tools on the install CD for OS X any how. Windows computers are essentially unprotected any way. So I really don't see how it's any worse then plugging in a USB stick to access everything or change the password (SAM) to blank/whateveryoulike. Screaming about a ten year old feature is just dumb. Just set up a firmware password and it stops people from simply booting a CD, USB-drive, HDD-drive, using target disk mode and network boot any way. It's simply not more vulnerable then PCs any way. It's quite easy to restore the firmware-password thus bypassing it on say an iMac any way, I could easily do it on older macs without taking the entire computer apart. And on a PC of course resetting CMOS password is often troubleless and manufacturers often has master passwords you get by calling the support any way. Later macs has got better protection from resetting the firmware password though. So just set the damn password.
Penti - Friday, July 8, 2011 - link
They are not driving the screen with a separate control-board. That's why target display is so awkward. You can expect third party stuff (and older macs) will work when Atlona has designed and released an Thunderbolt-compatible adapter/switch/converter/scaler though. It a integrated solution not a screen and a computer separate. The screen is when used normally connected directly to the ATi/AMD 6000M GPU. That's why you can't adjust the screen in Bootcamp/Windows without their software tool too.HW_mee - Friday, July 8, 2011 - link
That makes sense, not much you can do to separate the two things if the screen is "merged" with the computer. I expected the computer part and screen part was seperate and the display input could be used in the same way as with most multiple input screens.If that was the case, a simple power circuit could control the screen and computer separately.
youngjimmy - Friday, July 8, 2011 - link
'Failing to do so will give you this all-*to*-familiar error' (bottom, The Pegasus: Software)Kimbie - Friday, July 8, 2011 - link
You made mention about connecting up a monitor to the last port on the chain, by plugging in a thunderbolt cable into the imac and used it as a second screen.Does this still work if you use a mini-display port to DVI adaptor and into a bog standard DVI monitor?
Kimbie
Focher - Saturday, July 9, 2011 - link
Just to clarify, the last connection in the chain to a mini DisplayPort monitor does not require a Thunderbolt cable. You would just use a mini DP cable.André - Friday, July 8, 2011 - link
Does it support JBOD?Would be really great for us using ZFS+ arrays, although I would have preferred at least 8 bays.
Exodite - Friday, July 8, 2011 - link
The performance is impressive, though nothing like what you'd get transfering a large number of smaller files obviously.That said, for 2000 USD why wouldn't I simply build a high-end desktop /with/ 12TB of storage?
It'd still be cheaper and I could put the remainder towards a gilded sticker for the case saying 'cheap-ass NAS'.
André - Friday, July 8, 2011 - link
It would appear that is the solution for you, building your own NAS.This enclosure is, however, not a NAS.
It enable users that need high disk performance to get easy access to precisely that in a mobile package you can take on the road with you and edit in the field.
Think large Final Cut Pro (or any other NLE), Logic Studio and Photoshop projects.