Promise Pegasus R6 & Mac Thunderbolt Review
by Anand Lal Shimpi on July 8, 2011 2:01 AM ESTThe Pegasus: Hardware
Promise offers two versions of the Pegasus: the R4 and R6. The names are easy enough to understand, they simply refer to the number of drive bays. Through Apple you can buy any of four configurations:
| Promise Pegasus Lineup | ||||||
| # of Bays | Drive Configuration | Default Capacity | Price | |||
| Promise Pegasus R4 4TB | 4 | 4 x 1TB RAID-5 | 2.7TB | $999 | ||
| Promise Pegasus R4 8TB | 4 | 4 x 2TB RAID-5 | 5.7TB | $1499 | ||
| Promise Pegasus R6 6TB | 6 | 6 x 1TB RAID-5 | 4.7TB | $1499 | ||
| Promise Pegasus R6 12TB | 6 | 6 x 2TB RAID-5 | 9.7TB | $1999 | ||
All of the configs ship with 3.5" 7200RPM hard drives and are configured as a single RAID-5 array by default, although Pegasus supports most of the common RAID formats (RAID 0/1/5/50/6/10).
The 12TB Pegasus R6 we received for review came with 6 x 2TB Hitachi Deskstar 7K3000 drives. These are four platter drives with 64MB buffers. I did try installing Seagate 3TB drives and SandForce SF-2281 SSDs in the system, both of which worked. I did run into some reliability issues with the Pegasus R6 configured with 4 x SF-2281 SSDs, however it's unclear whether they were caused by the drives themselves, the Pegasus or a combination of the two.
Internally Promise uses a PMC Sierra PM8011 8-port SAS-2 RAID controller. This is an 8-lane PCIe Gen 2 controller with eight SAS/SATA 6Gbps ports. On the R6 obviously only six of those ports are functional. The PM8011 has an embedded 600MHz MIPS processor and is paired with 512MB of DDR2-533.
The Pegasus chassis is made out of aluminum, similar to the unibody MacBook Pro and iMac but not quite identical. The color is a bit lighter with a more coarse grain. The metal construction combined with the six 3.5" drives gives the Pegasus R6 its 20.4 lbs weight (the R4 weighs in at around 15 lbs).
The front of the chassis is pretty clean. The glossy black strip on the left of the unit is home to the power button and the two Thunderbolt indicators. There are two Thunderbolt ports on the Pegasus, one connects to your Mac while the other connects to any other DisplayPort/Thunderbolt devices in the chain. Occupy a single port and one indicator lights up, occupy both and you get two:
The power button burns blue when everything is functional, orange during startup and red if there's a problem with the array. Powering down the Pegasus requires that you hold the power button for ~10 seconds until the button glows red then release in order to avoid any accidental shutdowns.
The R6 has six removable 3.5" drive bays that accept 2.5" drives as well. The screws Promise provides with the Pegasus are too large for SSDs so you'll have to supply your own if you want to replace the HDDs with SSDs down the road.
Ejecting and inserting the Pegasus' drives is incredibly smooth. There's a large square eject button on the front of each drive carrier - depress it and the handle pops out. Pull on the handle and the drives slide out perfectly. There's surprisingly little resistance to inserting the drives completely, the entire motion is just very fluid.
Each carrier has two LEDs - status and activity. Blue indicates proper operation while red indicates a problem.
The Pegasus' on-board RAID controller doesn't care about the order in which you install drives for a single array (e.g. you can swap carriers 2 & 5 and your array will still function, provided you do so while the Pegasus is powered down). Note that if you do remove more than one drives from an live RAID-5 array you'll lose all of your data, even if the array was idle when you pulled the drives. You can remove a single drive and be fine, although you'll have to resyncrhonize the array when you insert the missing drive. A full RAID-5 rebuild takes about 7 hours on the Pegasus R6. The array is still usable during its synchronization process.
Around back there are two Thunderbolt ports and a serial port, the latter presumably for firmware updates/direct access to the on-board controller (the port is currently undocumented).
There are two fans in the Pegasus R6: a large ~100mm fan to cool all of the drive bays and a small ~40mm fan to cool the integrated PSU. The Pegasus ships with a 250W 80Plus Bronze certified power supply. The PSU isn't intended to be user serviceable and can't be removed without disassembling the Pegasus.
The Pegasus is powered by a standard 3-pin AC power connector. Promise supplies a cable although any standard PC power cable will work.
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darwinosx - Friday, July 8, 2011 - link
Hardly anyone uses projectors so VGA ports should only be on business class laptops.Zok - Friday, July 8, 2011 - link
Can't say I agree with you there. Despite being issued a corporate laptop, I use my personal one for most of my work, including (VGA-requisite) projector presenting.cacca - Friday, July 8, 2011 - link
some questions:Does USB 3 port do the same?
Does the PCI-E external do the same?
Does External SATA do the same?
Thunderbolt is just another PROPRIETARY standard that competes with others.
It reminds me RAMBUS.
were cost and compatibility matters. Is faster but....
We will ever seen a review of something from Intel that points out the shortcomings?
or this place is ADDtech instead of anandtech?
André - Friday, July 8, 2011 - link
Rest assured that USB 3.0 does NOT in any way or form do the same as Thunderbolt.The protocols are very different, as in, USB 3.0 nearly doesn't support any and Thunderbolt being an extension of a 4 x PCI-Express slot does support heaps of features, like Target Disk Mode, S.M.A.R.T.-status, Native Command Queuing, daisy-chaining (with very low latency) making it ideal for many professional applications (Audio/Visual devices), bi-directional bandwidth, DisplayPort, 10 Watt of power and native software driver support.
Just to name a few.
External SATA doesn't do the same either.
Thunderbolt is a multi-purpose connector, not limited to only storage or transfer of files.
If you for a minute think that USB or E-SATA does the same as Thunderbolt, then you need to educate yourself.
It has the potential to replace all other external connectors. One cable to rule them all, instead of legacy cables that clutter up the backside of your computer and collect dust.
Anato - Friday, July 8, 2011 - link
And one controller (maker) to rule us all. Thats a big problem in PC, but not necessarily in Mac.Jaybus - Sunday, July 10, 2011 - link
Not really. Light Peak is essentially protocol agnostic. It tunnels PCI-E. The PCI-E-to-whatever bridge is built into the cable and/or dongle. In other words, a USB 3.0 adapter/hub that plugs into a Light Peak port is possible and even likely.While Intel may control the Light Peak controller, which will no doubt be integrated into motherboard chipsets, I don't think that will give them a monopoly on the bridge chips that make LP actually useful.Exodite - Friday, July 8, 2011 - link
Cue 'potential'.It's not hard to foresee another Firewire or mini-DP in the making, or a Beta if you prefer going old-school.
Coupling Light Peak technology with mini-DP was a mistake. The technology is new, unproven and offers precious few usage scenarios with non-existent device support. Piggy-backing it on mini-DP, which suffer from pretty much exactly the same issues, won't help adoption rates.
Choosing USB over mini-DP as the 'legacy' interface would have been a much better choice.
André - Friday, July 8, 2011 - link
Except that the USB connector is only allowed to be used as an USB connector.DisplayPort is also vastly superior to any other display cable standard, so I cannot see the problem in that regard. Mini-Display is already shipping in millions and millions of computers, as well as Mini-DisplayPort. The same can be said by Thunderbolt, even though it is only Apple who have fully embraced the technology.
As a professional in the audio/visual segment I can hardly see the problem with it being a repeat of FireWire, because my market usually adopts the better technology despite of a small price increase. Of course, it helps that we only use Apple computers to begin with and have already ditched all the back-alley, legacy connectors.
Uritziel - Friday, July 8, 2011 - link
Heh, yet another continuation of the myth that media professionals only use macs...André - Friday, July 8, 2011 - link
Kindly don't put words in my mouth ;)I didn't say media professionals only use Apple computers, I said my company only use them.
As for now it only makes sense to discuss Thunderbolt and Apple computers as Apple are the only ones who has it currently.
But you just have to look at the companies that are releasing Thunderbolt enabled devices to understand that this connector is really something professionals are going to use. Next year the market will open up when PC vendors finally, if they so choose, to embrace the technology.