Promise Pegasus2 M4 (4x1TB) Thunderbolt 2 DAS Review
by Kristian Vättö on September 12, 2014 9:00 AM EST- Posted in
- Storage
- Thunderbolt
- m4
- Promise
- DAS
- Thunderbolt 2
- Pegasus2
The Pegasus2 M4: Software
Since my only Thunderbolt-enabled system is Windows based, our look at the software is limited to the Windows version, but our original Pegasus R6 review has screenshots from the OS X software.
For managing the M4 and other products, Promise offers WebPAM PRO software. It is web-based software that runs in the browser and upon launching it will ask for your Windows user's credentials before you are granted access to WebPAM PRO. The dashboard view just gives a quick overview of the device and its status.
The device tab offers a real-time graphical view of the device and its components. Clicking either the device graphic or the list on the upper right corner will give more details about the enclosure, controller, and physical drives. Below is a gallery with additional screenshots that shows what exactly the WebPAM PRO allows you to monitor.
Creating the array can be done under the storage tab and once again you are presented with a real-time graphical view of the device. To select the drives you want in the array, simply click the drive bay and it will turn blue. Once you have selected the bays you want, the submit button will lead you to the next screen.
The final step is to set the RAID level and other specific aspects. RAID 5 is the default RAID level in the M4 as it comes with a hardware RAID controller, but RAID 0 and RAID 10 are supported as well.
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Zak - Friday, September 12, 2014 - link
The 4xSSD performance is a little disappointing indeed. That would be #1 reason to get this enclosure. I get faster speeds, over 1GB/s reads, out of two SSDs on the onboard Intel RAID controller.simonrichter - Friday, October 3, 2014 - link
I agree, it is rather disappointing and it makes it an average storage devices that cannot match up to the top ones on the market (for example http://www.consumertop.com/best-computer-storage-g... ). But it should be interesting to see if they release an updated version of it.jonb8305 - Wednesday, October 15, 2014 - link
Promise has an SSD version of the m4 with way better performance than what was stated here.bill.rookard - Friday, September 12, 2014 - link
While I do somewhat see the use of a device like this, I'm not sure I see it really serving any real niche effectively.It's made to use small, portable drives, but it's not portable as it requires external power.
It should be quick, but it's limited by the internals to about 1/4 of it's theoretical top speed.
It uses the expensive Thunderbolt interface to be fast, but again, it's limited internally.
It offers four drives, but keeps them to 2.5" drives without making the unit truly portable.
It offers four drives for capacity, but then only offers 1TB drives.
This device just seems like a whole series of compromises without really SERVING a niche effectively.
JohnMD1022 - Tuesday, September 16, 2014 - link
Why not offer it as a bare box?Drizzt321 - Friday, September 12, 2014 - link
How about running the SSDs as single disks and using Windows RAID to check performance. Cut out the RAID controller, which them will leave us the SATA controller to test that to see if it's the RAID controller, or the SATA controller.And I agree, it's too bad it can't be bus-powered. Maybe when USB3.1 with Type-C connectors comes along it'd be able to power something like this. 100W is quite a bit of power, especially with 2.5" drives!
repoman27 - Sunday, September 14, 2014 - link
If Kristian was correct in his guess that there's a PMC-Sierra PM8011 lurking under that heat sink, which is quite likely seeing as Promise uses that chip in several other products already, it's an RoC (RAID-on-Chip). So the SATA (actually SAS in this case) controller and the RAID controller aren't terribly separable.The performance scaling actually looks damn near perfect with the HDDs, and indicates that the RoC is actually a beast for the intended workload. I'm not sure why Kristian thought RAID 5 read performance would be higher. If you only stripe across three drives and write parity data to the 4th, it would be pretty challenging to read back faster than 3x the maximum a single drive can muster. In this case, the Pegasus2 M4 hit 355.5 MB/s vs. 120 MB/s for a single drive, or near as makes no difference 3x. And the 15% performance hit for sequential reads in RAID 10 doesn't seem too egregious, especially seeing as random reads went up by almost 17%.
Kristian never mentioned what he was using for SSDs or if they were all identical. I'm guessing whatever he used, the RoC simply wasn't tuned for it. Although who knows, maybe the same test on a Mac would have yielded radically different results.
100 W may be a lot for 4x 2.5-inch HDDs, but the Pegasus2 M4 appears to be packing a compact internal 110 W PSU from FSP. That's nuts!
HigherState - Friday, September 12, 2014 - link
I know they say performance on win vs mac should be close, however those numbers are so dissapointing that its possible that its os driver related as well. Someones bound to have an old MBP to lend you for the testrepoman27 - Sunday, September 14, 2014 - link
Well, the performance of the unit as it shipped isn't really disappointing at all. I mean, aside from not using something slightly peppier than the Toshiba drives, like maybe HGST Travelstar 7K1000's, what was Promise supposed to do?Clearly the SSD experiment was performed with a set of drives that had in no way been validated against Promise's firmware.
The_Assimilator - Friday, September 12, 2014 - link
Or you could spend $700 on four 7200rpm 4TB 3.5" drives and a cheap RAID controller card, and build a RAID-10 setup that also wouldn't be portable, but would be fast and have 8 times the capacity of this POS.