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Review: Promise Pegasus2 Thunderbolt 2 RAID array for Apple's latest professional Macs

post #1 of 34
Thread Starter 
Promise Technology's Pegasus2 RAID storage solution was one of the first products to sport the latest Thunderbolt 2 , offering blazingly fast read/write speeds for data-intensive operations.

Pegasus2


Following Intel's announcement of Thunderbolt 2 in January 2013, products harnessing the super-fast transfer protocol are finally coming to market. Apple's late-2013 MacBook Pro with Retina Display was the first computer to incorporate Thunderbolt 2, but at the time there were few accessories that supported the technology. Promise changed that in December when it launched the world's first Thunderbolt 2 RAID array.

Built around the PMC Sierra 8011 RAID-on-chip processor, Promise's Pegasus2 controller comes with 512MB of DDR2 SDRAM to push data through Thunderbolt 2's bi-directional 20Gbps channel. The version we tested, dubbed the R4, comes with four 2TB 3.5-inch 7200RPM SATA drives preinstalled; in our case units from Toshiba. Pegasus2 also comes in 6- and 8-drive configurations with support for 2.5-inch SSDs as well as 2.5-inch and 3.5-inch Hybrid HDDs.

Design



The Pegasus2 is identical to the previous generation Pegasus save for a color swap from silver to matte black. Not a huge difference, but the change is a nice touch that keeps with Apple's new all-black aesthetic seen with the Mac Pro.

Pegasus2


As seen in the photos above, a translucent strip of plastic runs down the left side of the enclosure. Two LEDs situated behind the feature glow blue when a Thunderbolt cable is attached to one of the rear input ports. A tactile power button with integrated multi-colored LED is set near the top of the plastic bar and acts as an onboard system status light.

Positioned on the right of the enclosure are the hard drives, which are attached to Promise's easy-open carriers. As with many newer multi-drive direct and network attached storage products, the Pegasus2 ditches key-and-lock or screw-type bays that were often difficult to operate (or near impossible if you happened to lose the key).

Pegasus2


As with the first-generation Pegasus, the Thunderbolt 2 model features spring-loaded drive carrier handles that disengage from the cage with the press of a button. Once released, the plastic handle pivots outward as seen above, allowing for easy removal and drive swapping.

The system is fairly well protected against accidental drive removal as the user must first apply a decent amount of pressure to disengage the button lock, then physically pull the drive out of its socket via the handle.

Pegasus2


A pair of LEDs on the drive carrier show drive status and activity for that particular bay. For example, if a drive was removed accidentally and reinserted, the system would consider it dead and the status light would turn red. The activity LED glows blue when a drive is detected and blinks when the drive is active.

For a four-disk array, the R4 is solid but not overly heavy, coming in at slightly under ten pounds empty. With four drives installed, the weight jumps up to over 15 pounds, though the package is still manageable and can easily be moved around a workspace if needed.

Pegasus2


On the back, a large low-RPM fan sucks heat out from the drive portion of the chassis, while a smaller blower pushes air over the controller circuitry. Both fans were near silent when spooled up to operating speed and allowed to run for extended periods. Sound dampening is enhanced by four large vibration-absorbing rubber feet.

Above the larger fan are the R4's two lone Thunderbolt 2 ports. The positioning makes it ideal for blind plugging and unplugging, but depending on unit placement, the hot exhaust air tends to collect near the cable plugs. While temperatures remain well within spec of the Corning Optical Cables we were using, over time the warm air may degrade lower quality connectors.

Pegasus2


Setup



For reference, we mated the R4 with a quad-core 2013 Mac Pro and Apple's latest MacBook Pro with Retina Display, both of which boast Thunderbolt 2 ports. For interconnects, we used Corning's Optical Thunderbolt Cables, Apple's Thunderbolt cable and the unbranded model provided by Promise.

Pegasus2


Powering the unit up from a cold start takes about 20 to 30 seconds depending on the RAID configuration. Once on however, the drives spin up in seconds, making the logical drive accessible when waking a Mac from sleep. Users can turn the unit on or off via the physical power button or by unplugging the Thunderbolt cable.

Pegasus2


A warning note comes with the unit, instructing users that their new array must be plugged in and attached to a host computer in order to properly build the logical drive. The process takes quite some time to complete -- in our case a little under five hours -- and mileage will vary depending on storage size.

It should be noted that OS X will recognize the R4 as a single logical drive, meaning the global Energy Saver settings in System Settings apply. For example, when we left the array attached to our 2013 MacBook Pro with Retina Display, Mavericks would spin the drives up when Power Nap was enabled. On the Mac Pro, we left the "put hard drives to sleep" option unchecked, thus defaulting the R4 to the Promise Utility software's settings.

Promise pre-configures its Pegasus2 arrays from the factory in RAID 5, a "best of both worlds" level that offers good speeds and redundancy across the four physical drives. The R4 can handle RAID 0, 1, 1E, 5, 6 and 10 (1 + 0), while the larger R6 and R8 support RAID 50 (5 + 0). The biggest of the bunch, the eight-drive Pegasus2 R8, is capable of RAID 60, otherwise known as RAID 6 + 0.

Pegasus2


In its stock RAID 5 configuration, the R4 was plenty fast with the striped setup and distributed parity. For those wanting more speed or safer mirroring configurations, Promise offers an automated "Wizard" utility that can set up the array and logical drive to desired specifications.

Those just starting out with RAID arrays don't need to fiddle with the settings, but the GUI-driven tool offers professionals and power users the ability to reconfigure their arrays, add non-matching drives and diagnose problems. In addition to the setup features, the Promise Utility also gives a comprehensive real time look at system vitals like temperature, I/O speeds and other metrics.

In use



Pegasus2 lives up to the Thunderbolt 2 hype. In our tests the logical drive clocked in with speeds up to 540MB/s read and 454MB/s write, while real-world sustained speeds came in at just below 300MB/s. This is more than enough bandwidth to edit full resolution 4K video in real time.

Pegasus2


Thanks to the Mac Pro's six Thunderbolt 2 ports and three buses, we were able to drive Sharp's gorgeous 4K monitor on one bus while keeping the Pegasus2 routed separately for maximum throughput.

Read and write speeds did not come close to hitting Thunderbolt 2's 20Gbps barrier. When using a 4K monitor, however, the story changes somewhat considering the available pipeline will be mostly reserved for pushing pixels. Those with a Mac Pro have little to worry about here, but MacBook Pro owners may find diminished bandwidth depending on setup and workflow.

For many users, the Pegasus2 can be a completely plug-and-play machine for file backups, Time Machine saves and multimedia storage, though the product's real power lies in its ability to access huge amounts of data at high speeds. With Thunderbolt 2, accessing mass storage is no longer the bottleneck for professional workflows. This means -- in most cases -- no transferring footage to an internal drive for rendering or waiting for data to load.

Using the device is straightforward as the single RAID 5 logical drive is easily accessible from the desktop (or in the system folder). Drag-and-drop is of course supported, as are other consumer-minded features.

The Pegasus2 offers a fairly deep selection of settings, control and monitoring tools in Promise Utility, making the package a good choice for professionals as well. For example, users have access to advanced RAID controller information like data transfer speeds, I/O requests, errors, data transferred and other statistics.

Pegasus2


Some controller settings are also customizable and include SMART data retrieval, cache flushing and coercion method, among others. This is in addition to the usual hardware monitoring information like drive and enclosure temperatures, fan speed and system stability data.

We also tested out the Promise Utility's "Background Activity" tools, which contains a suite of software assets for automatically managing the drives. All operations can be set to run according to a scheduled or predefined set of time parameters.

Pegasus2


For example, Media Patrol monitors the viability of HDD hardware, while Redundancy Check checks for properly matched data in redundant (mirrored) disk arrays. These disk health tools come in handy for critical data applications, acting as a kind of secondary protection against data corruption or loss.

The remaining Background Activity tools allow users to configure storage capacities, change RAID levels and initialize the logical drive. All the features worked as advertised, though we would have liked to see a bit more granularity in scheduling tasks.

Rebuilding

No RAID array would be complete without a rebuild function. For this test, we yanked one of the physical drives out of the R4, causing an immediate and critical logical drive error. As seen in the screenshot below, the system automatically put the three remaining drives into power saving mode to prevent data corruption.

Pegasus2


To simulate a dead drive, we left the HDD removed and reactivated the remaining HDDs. In our tests, all data was present as parity was distributed across the drives. RAID 5 requires at least three active HDDs to ensure complete data parity, however, so we removed another drive.

Pegasus2


As expected, the R4 refused to be recognized by OS X as a logical drive, though the Promise Utility was able to maintain physical drive statistics. To rebuild, we reinserted the drives and opened the Promise Utility's Rebuild feature -- confusingly located in "Background Activities." The software walked us through the process of selecting source and target drives, renaming the new physical drive and creating a new alias for the logical drive. The software takes over from there. Overall, the process took less than 15 minutes.

Conclusion



The Promise Pegasus2 is a well designed and managed DAS with top-of-the-line hardware backed by a comprehensive software suite. More than enough for the average user, the package is easy to recommend for those who value speed over cost. At $1500, the complete setup is pricey for the everyday consumer, but not outrageously expensive for professionals.

Pegasus2


To be clear, the R4's performance is solid and can be used as a workhorse. The only drawback with the four-bay design is its limited capacity. Pros will definitely want to spring for the six- or eight-drive models, especially when using non-striped redundant RAID levels.

Score: 4.5 out of 5



ratings_hl_45.png

Pros:



  • Fast sustained I/O speeds
  • Quiet operation
  • Powerful utility and diagnostics software


Cons:



  • Limited storage capacity
  • Bland design
  • Speed comes at a price


Pricing and availability



The 8TB Pegasus2 R4 retails for $1499 and is currently available for $1,454 complete with drives pre-installed. Promise's larger R6 comes in 12TB and 18TB configurations and sells for $2,230 and $2,900, respectively. Finally, the 24TB and 32TB R8 come in at $3,491.00 and $4,460.

These are currently the lowest prices we could find for these drives, with the added benefit of no sales tax outside of NY. This will account for an additional $115 to $350 in savings, depending on the model. You can also check prices daily in AppleInsider's Mac Storage Price Guide.

We were fortunate enough to test the 8TB Pegasus2 R4 for several weeks, but the drives were initially hard to secure. As such, we'd also like to thank B&H Photo for its help in securing one.


bh_appleinsider-promise.gif
post #2 of 34
Quote:
Originally Posted by AppleInsider View Post
AppleInsider also thanks B&H Photo for its aid in sponsoring this review and helping to make it possible. The retailer's prices can be compared daily against other resellers in AppleInsider's Mac Storage Price Guide.

 

How can we trust that the review is objective?  If the review concluded that readers should not buy this product, would B&H ever sponsor another?

post #3 of 34
So for those of us who simply want to add some external storage, say a single 3.5" 2TB 7200RPM, do we need Thunderbolt? Or is USB3 fine?

USB has the advantage to working with practically any computer, as well as being far less expensive. But will I notice any performance difference at all?

Sure, TB is much faster than USB, but both are MUCH faster than any single HD, right?
post #4 of 34
Quote:
Originally Posted by SudoNym View Post
 

 

How can we trust that the review is objective?  If the review concluded that readers should not buy this product, would B&H ever sponsor another?

Because we take pride in abiding by a code of ethics. Our editors wanted to bring this review to AppleInsider readers. We asked for B&H's help -- not the other way around -- in securing one in a timely fashion after the original manufacturer was not responsive to routine requests. It was nice of them to help, so we thanked them. They also are one of only a handful of stores, including Apple's, that currently stock the device. For most US readers, they also currently have the lowest final price by a considerable margin. We noted that in the review -- as we always do in the "buy" section -- and directed readers to the full price guide to compare with their competitors. Thanks.

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post #5 of 34
Quote:
Originally Posted by AppleInsider View Post

Pegasus2 lives up to the Thunderbolt 2 hype. In our tests the logical drive clocked in with speeds up to 540MB/s read and 454MB/s write, while real-world sustained speeds came in at just below 300MB/s. This is more than enough bandwidth to edit full resolution 4K video in real time.

Read and write speeds did not come close to hitting Thunderbolt 2's 20Gbps barrier. When using a 4K monitor, however, the story changes somewhat considering the available pipeline will be mostly reserved for pushing pixels. Those with a Mac Pro have little to worry about here, but MacBook Pro owners may find diminished bandwidth depending on setup and workflow.

Thunderbolt 2 is not really needed for a drive like this but it does mean you'd be able to put a 4K display on the same chain. A 4K display would need 3840 x 2160 x 60Hz x 24-bits = 11.9Gbits/s or 1.5GBytes/s. Thunderbolt 2 is 20Gbits/s or 2.5GB/s. But it wouldn't be necessary to do this even on a MBP as they have two Thunderbolt 2 ports.

It's only SSD drives that get the benefit of Thunderbolt 2 so the Pegasus would have to be filled with those. Lacie's Thunderbolt 2 drive shows the performance possible:



A single drive with dual SSD blades up to 1TB runs at 1.1GB/s write, 1.3GB/s reads. Two of them on a chain in RAID0 runs at 2GB/s write, 2.5GB/s reads. Where the HDDs win is on price per GB. 1TB SSD is $1000, 8TB Pegasus is $1500. So SSD is around 5x more. If you were to get SSDs separately, you can get 1TB drives for about $500 for 1TB so say you get an 8-bay enclosure for $1500 with no drives and 8x $500 1TB SSDs, that's $5500 vs $1500, then SSD is 3.5x more.
Quote:
Originally Posted by Maury Markowitz 
So for those of us who simply want to add some external storage, say a single 3.5" 2TB 7200RPM, do we need Thunderbolt? Or is USB3 fine?

USB has the advantage to working with practically any computer, as well as being far less expensive. But will I notice any performance difference at all?

Sure, TB is much faster than USB, but both are MUCH faster than any single HD, right?

USB 3 is fine for single drives as it is roughly as fast as the SATA connector and especially HDDs as they are about 1/5th that speed. A single SSD over USB 3 is actually faster than this HDD Pegasus over Thunderbolt. This doesn't have much to do with USB 3 vs Thunderbolt, there are cheaper Thunderbolt drives too:

http://www.amazon.com/BUFFALO-MiniStation-Thunderbolt-Portable-Drive/dp/B008D4X9UI
post #6 of 34
Quote:
Originally Posted by Maury Markowitz View Post

So for those of us who simply want to add some external storage, say a single 3.5" 2TB 7200RPM, do we need Thunderbolt? Or is USB3 fine?

USB has the advantage to working with practically any computer, as well as being far less expensive. But will I notice any performance difference at all?

Sure, TB is much faster than USB, but both are MUCH faster than any single HD, right?

I am waiting for prices to come down and more options to go TB2 RAID. In the meantime, to answer your question, I bought a $35 EZ Dock dual bay USB3 dock on Amason, used a couple of SATA 3, 7200, 2 TB drives I had lying around and used Apple Disk Utilities to create a 4 TB RAID 0. I also have a 6TB set also. This all took about two minutes start to finish. Not much use for editing 4K maybe but pretty snappy I think you would agree. By the way the Mac Pro (a 6 Core 2013) was also creating a .dmg from an external DVD reader at the same time to another external drives attached to a different USB3 IO, I could not be bothered to wait for it to finish but it doesn't seem to have caused any slowdown on the RAID.



For TB 1 there is a nice dock here but a lot more $s than a USB3 dual dock mentioned above, if you don't need the extra speed USB3 is pretty nice.
http://www.amazon.com/dp/B00DJ3YEH0/ref=wl_it_dp_o_pC_S_img?_encoding=UTF8&colid=2O638I77MEVNB&coliid=I3JDONC3OQYMRB
but of course you can't have RAID 5 with two drives but you can have a RAID 0 for non critical work such as capturing HD video etc.
Edited by digitalclips - 2/4/14 at 8:03am
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nMac Pro 6 Core, MacBookPro i7, MacBookPro i5, iPhones 5 and 5s, iPad Air, 2013 Mac mini, SE30, IIFx, Towers; G4 & G3.
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post #7 of 34

I bought one of these about a month ago. I'm using it with a late 2013 iMac, so it doesn't have Thunderbolt 2. But I do see roughly the same performance as in the review. Real-world performance does tend more toward the 300 MB/s range, which, since I'm not using it for 4K video or anything that requires massive bandwidth, is plenty fast for my workloads.

 

The one thing I disagree with in this review is around noise. The fans on my unit are not ridiculously loud, but it's definitely noticeable. That's disappointing because the Mac itself is completely silent. One of these days I'll probably break down and buy an optical Thunderbolt cable so I can hide it in the closet, but that's $300+ I'm not going to spend right now :-)

post #8 of 34
Quote:
Originally Posted by Maury Markowitz View Post

So for those of us who simply want to add some external storage, say a single 3.5" 2TB 7200RPM, do we need Thunderbolt? Or is USB3 fine?

Sure, TB is much faster than USB, but both are MUCH faster than any single HD, right?

 

For most consumers USB would work just as well as TB.  TB comes into play when you're transferring large amounts of data off very fast drives (RAID or SSD).  One of the advantages of TB over USB is when you have multiple drives, the daisy chaining is a more elegant solution to using a hub or multiple USB ports on your computer.

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post #9 of 34
Quote:
Originally Posted by Kasper View Post
 

Because we take pride in abiding by a code of ethics. Our editors wanted to bring this review to AppleInsider readers. We asked for B&H's help -- not the other way around -- in securing one in a timely fashion after the original manufacturer was not responsive to routine requests. It was nice of them to help, so we thanked them. They also are one of only a handful of stores, including Apple's, that currently stock the device. For most US readers, they also currently have the lowest final price by a considerable margin. We noted that in the review -- as we always do in the "buy" section -- and directed readers to the full price guide to compare with their competitors. Thanks.

Did you check OWC/MacSales? They show 24-48 hrs. I know Promise has an online store but it doesn't look like they sell the Pegasus line through their store, only through resellers. I don't work for Promise Technology but I did contact them on December 11, 2013, asking about the part number for an empty 4-bay Pegasus2 (P/N P2R4HD0US) and I got a response the next day. Maybe I was asking an easy question. :-)

 

post #10 of 34
Do you have to install a driver under OS X for this device to be recognized as a single drive?

Does the RAID level in this device manage itself once it has been built without relying on OS X? I realize in order to initialize and build a RAID level, this device has to be connected to a Mac running OS X.

However, once RAID has been built, can this device be connected to a Mac Mini running VMware ESXi and be seen by ESXi as a single external drive? My goal is to use a Thunderbolt storage device like this as the DAS for hosting ESXi datastore(s).
Edited by sirozha - 2/4/14 at 9:23am
post #11 of 34
Quote:
Originally Posted by AppleInsider View Post

The version we tested, dubbed the R4, comes with four 2TB 3.5-inch 7200RPM SATA drives preinstalled.

There lies the problem: you want to get your drives from different batches/brands. Not from a single batch, as is most likely the case when ordering. But alas, can't get the box with the drives. Possible because they wouldn't make any money on it, or it would be considered overpriced.
Quote:
Pegasus2

Thank you for this picture; we never get to see the innards in reviews; well done!
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post #12 of 34
Quote:
Originally Posted by AppleInsider View Post

Promise pre-configures its Pegasus2 arrays from the factory in RAID 5, a "best of both worlds" level that offers good speeds and redundancy across the four physical drives. The R4 can handle RAID 0, 1, 1E, 5, 6 and 10 (1 + 0), while the larger R6 and R8 support RAID 50 (5 + 0). The biggest of the bunch, the eight-drive Pegasus2 R8, is capable of RAID 60, otherwise known as RAID 6 + 0.

 

It would be interesting to know what the other Raid options might be. For instance, can four drives be configured as two separate pairs of Raid 0 or 1? Or as four independent disks? (Yes, I do understand the redundancy trade-offs.) TB2 has enough bandwidth to make these other options potentially interesting, depending on the user's needs.

post #13 of 34
I purchased the Promise Pegasus2 R6 18 TB model about three weeks ago, and I have been using it since then with a fully massed out new Mac Pro. Overall, I am in agreement with this review, and I find my Pegasus2 R6 to be a quiet and very fast storage system.

I do have two points to make about the Pegasus2 R6 that I received.

First, when I initially hooked it ups and began using it, I found that the HD's in the raid were always having to spin up very time I tried to access the Pegasus2. This was in spite of the fact that in System Preferences>Energy Saver I did NOT have Spin Drives Down When Possible checked. I managed to contact a Promise support person through Larry Jordan's Forum where a review of the Pegasus2 had been posted, and he was able to give me a command line set of instructions which, implemented through Terminal, allowed me to turn off all three levels of power management. Note that, at present, only the top level of the power management options can be turned off in the promise Utility. That solved the constant spin-up problem.

The second problem that I have found is that the backplane temperature on my Pegasus2 unit runs very close (within one degree) of the 53 degrees C. that triggers an orange warning in the Promise Utility and causes the fan in the Pegasus2 to run at a higher rpm making the Pegasus2 much more audible. This occurs when I am not addressing the Pegasus2 or using it under a heavy load such as when video editing. I sam going to have to contact Promise support and find out what is causing this problem or indeed whether I should even worry about it.

Promise has done a good job of demystifying raid and providing an extremely fast raid system with the Pegasus2 units.

Tom
post #14 of 34
Great Review!
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post #15 of 34

Can you give a bit more details on how the Pegasus config SW handles hetrogenous drive combinations?

 

I would like to use 2 SSDs as RAID-0 and add 2 large capacity standard HDs for backup & archive - is that supported?

post #16 of 34

is the power supply still internal?

 

i called them to get a spare power supply for the original thunderbolt case and was advised that i'd need to send the entire box in for replacement.

 

not good.

post #17 of 34
Quote:
Originally Posted by PhilBoogie View Post


There lies the problem: you want to get your drives from different batches/brands. Not from a single batch, as is most likely the case when ordering. But alas, can't get the box with the drives. Possible because they wouldn't make any money on it, or it would be considered overpriced.
Thank you for this picture; we never get to see the innards in reviews; well done!

Phil, not sure if you mean what you said but you always want to use matched drives in a RAID. This way they are all spinning the same and work the same, achieving the best performance. Promise sells most of their RAID systems with drives, not drive-less (like Areca). Apple sells a diskless version meant to be used with the old Mac Pro's 4 disks, http://store.apple.com/us/product/HE150VC/A/promise-pegasus2-r4-diskless-4bay-thunderbolt-2-raid-system?fnode=5f but everything else comes with matched drives.

post #18 of 34
Quote:
Originally Posted by sfmacguy View Post
 

is the power supply still internal?

 

i called them to get a spare power supply for the original thunderbolt case and was advised that i'd need to send the entire box in for replacement.

 

not good.

Some of this was covered elsewhere but I believe Promise warranties the entire unit, not specific parts, so having them fix or replace the entire unit (maybe also drives, not sure) means you should get a working replacement instead of dealing with other possible problems (nickel and dime yourself to death). 

 

http://www.promise.com/single_page_session/page.aspx?region=en-US&m=608&&rsn=64

post #19 of 34
Quote:
Originally Posted by sirozha View Post

Do you have to install a driver under OS X for this device to be recognized as a single drive?

Does the RAID level in this device manage itself once it has been built without relying on OS X? I realize in order to initialize and build a RAID level, this device has to be connected to a Mac running OS X.

However, once RAID has been built, can this device be connected to a Mac Mini running VMware ESXi and be seen by ESXi as a single external drive? My goal is to use a Thunderbolt storage device like this as the DAS for hosting ESXi datastore(s).

There aren't any drivers necessary. They do include a management application. Like all hardware RAIDs, the Promise systems manage everything inside the box. RAID level is configured using their application but once created, it should be able to operate on any computer that can write to an HFS+ partition. There are RAIDs available that use a switch on the box to configure the RAID setting but the Promise RAIDs have more features so a management application make more sense. Yes, you need to use this application to configure and manage the RAID.

 

As far as using it under ESXi running on a Mac, I checked and it looks like ESXi needs a Xeon 56xx series (MacPro5,1) to run ESXi 5.5. Maybe the older ones run on a Mac Mini but I doubt it. The Mac mini uses Thunderbolt-1 as well. If ESXi actually runs under OSX then it should be able to see the RAID since VMware generally has the disk drivers built into it to handle writing to an HFS+ drive from other operating systems. I run Fusion on my iMac using a Windows OS and it writes to it just fine. As far as using it as a DAS, it's my understanding a RAID, or any direct attached drive (USB included), operates just fine. I can't say for sure your ESXi configuration would work since I'm not sure whether you're actually running ESXi under OSX or under linux and just hosting various operating systems.

post #20 of 34
I don't think the array lives up to the hype when it comes to professional video work, especially 4K. The performance variation I see in the monitor graph does not give me a warm fuzzy feeling. Any performance you do get will NOT be solid sustained performance.

A bit of a let down.
post #21 of 34
ESXi runs directly on Mac Mini 6,2 hardware, which is quad-core i7 2012 Mac Mini. It also runs on 2011 Mac Mini. You can run ESXi 5.1 and 5.5 on Mac Mini 6,2. I've been running ESXi 5.1 for over a year on my Mac Mini 2012.

Also, I don't think the file system must be HFS+. If I were to use this device for datastores, it would have to be formatted in the file system that ESXi uses for formatting datastores.
post #22 of 34
&
Edited by sirozha - 2/4/14 at 6:31pm
post #23 of 34
Originally thought that I was posting new information last night (I was so excited to share about the diskless version), but after seeing an earlier post from Rob53, I realize I was being redundant and not adding anything new.

Rewrote my post to more confirm what Rob53 wrote, with my personal observation. I use my Pegasus2 R4 to hold my Lightroom Catalogues. So far I'm very pleased with the performance.

I purchased and received an diskless R4 case from Apple directly in late December and put my own drives into it. The process was fairly easy, but the instructions didn't really consider the diskless version.

There is a mixture of two manufacturers (all 3TB drives) in the array, and although it took ALL night to create the RAID6 drive, by my second cup of coffee in the morning it was ready. So far it works perfectly, and it has the capacity and speed that I would expect to have. The apple forums have people who claim to have put 4 TB drives inside, but I can't confirm, and of course they are rather expensive at the moment.
Edited by GoneNuts - 2/5/14 at 8:19am
post #24 of 34
Here is the direct link to Apple:

http://store.apple.com/xc/product/HE150VC/A
post #25 of 34
Quote:
Originally Posted by sirozha View Post

Do you have to install a driver under OS X for this device to be recognized as a single drive?

Does the RAID level in this device manage itself once it has been built without relying on OS X? I realize in order to initialize and build a RAID level, this device has to be connected to a Mac running OS X.

This is a RAID cabinet so it has the hardware to handle the array management built-in.   Once it's configured, it should present it's self as one storage device to whatever it's plugged into.  Technically, it looks like a raw device to whatever it's plugged into [theoretically, it could have multiple LUNs and present it's self as multiple raw devices].  If it's got a file system on it.. it'll mount.  If it doesn't it'll prompt you to partition/format it.

 

If it didn't have the RAID hardware built in, it would be considered a JBOD [Just a Bunch Of Disks].   JBODs will show up as individual disks when the device is plugged in and they can only be setup as a RAID if they're plugged into a RAID controller or if the computer creates the RAID with software.  That arrangement wouldn't be as portable.

post #26 of 34

It'd be nice to see some bandwidth tests in RAID0 or with the included drives swapped for SSDs.   From the numbers I'm seeing, this is what I'd expect from a small array of 7200RPM SATA drives. 

I'm not sure if the peak numbers reflect read and write from the cache.. not sure what you were doing to generate I/O.  I'd hope the cache is faster then 500Gb/sec.

 

I'm assuming the R6 and R8 use essentially the same controller if not an identical controller.  If we knew what the upper limits the controller on TB2 were, we'd be able to make some informed guesses about how performance might scale to the larger cases.

post #27 of 34
Quote:
Originally Posted by rob53 View Post

Phil, not sure if you mean what you said but you always want to use matched drives in a RAID. This way they are all spinning the same and work the same, achieving the best performance. Promise sells most of their RAID systems with drives, not drive-less (like Areca). Apple sells a diskless version meant to be used with the old Mac Pro's 4 disks, http://store.apple.com/us/product/HE150VC/A/promise-pegasus2-r4-diskless-4bay-thunderbolt-2-raid-system?fnode=5f but everything else comes with matched drives.

Excellent! Thanks for the link.

Well, maybe the make/model makes sense with your statement, but wouldn't you agree that getting drives from different batches will be safer than getting them from a single batch? There are a few data centers experts here, and more than one have stated that different batches is safer.
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post #28 of 34
Quote:
Originally Posted by PhilBoogie View Post

Excellent! Thanks for the link.

Well, maybe the make/model makes sense with your statement, but wouldn't you agree that getting drives from different batches will be safer than getting them from a single batch? There are a few data centers experts here, and more than one have stated that different batches is safer.

Makes sense to me.

Meanwhile I dream of 5 TB SSDs for $120. 1smile.gif
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post #29 of 34

Rob,

 

GoneNuts says he was able to set up a heterogenous RAID, although I agree with your point about matching drives in a RAID.

 

But my question was, can you mix both RAID (eg 2 RAID-0 drives) and non RAID drives in the Pegasus?

post #30 of 34

Just a thought about matching drives.  

 

I understand the desire to have matching drives on the front end.  But I think we should expect a RAID system to handle non-matching drives fairly well, as long as we conform to some standards.  Even if we go to some trouble to match drives when we create our drive, eventually one or more drives will fail and need to be replaced.  Should we expect that replacement drives be matched as well?  I think this can be a slippery slope.

post #31 of 34
Quote:
Originally Posted by digitalclips View Post

Meanwhile I dream of 5 TB SSDs for $120. 1smile.gif

We're gonna so laugh at this in 202x 201x.
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post #32 of 34
The OS running on a computer to which this RAID box is connected has to have a driver if this is a hardware RAID. I bet Apple has included the driver in OS X for this RAID DAS.

My goal is to connect such a RAID DAS to VMware ESXi. It would have to have the correct driver installed to recognize the hardware RAID controller in the Pegasus.
post #33 of 34
Quote:
Well, maybe the make/model makes sense with your statement, but wouldn't you agree that getting drives from different batches will be safer than getting them from a single batch? There are a few data centers experts here, and more than one have stated that different batches is safer.

Definitely use the same Make and Model.  You want the members of the Array to all have the same performance characteristics.  When you're taking a stream of data, breaking it up, and writing it across multiple disks, you don't want to have 1 member with slower write speeds than the others.  

 

You can make an argument either way on batch.   

 

Your co-workers are taking the position that the drive manufacturer may have production runs that have common manufacturing issues.  As a result, if you just happen to have 4 drives from that run in your Promise box, you're likelihood of a multi-drive failure is higher.  Single failures are a pain.. multiple contemporaneous failures are a disaster. 

It's not an unreasonable assumption.. I've seen more than a few examples of bad batches of components over the years.. everything from iBook video connectors to video chips to hard drives.

 We had a 36hr work day last year when multiple Seagates in one of our SAN boxes died before the first and second spare could rebuild parity.  Given we were running RAID 50 with two spares.. uptime was a big deal.

 

I could make a valid against mixing batches too though.. at least that it's not worth the effort.

If we accept the assumption that certain production runs of generally good drives have unusually high failure rates due to manufacturing issues during that run, then we're increasing our chance of getting a drive from a bad production run by 4x if we use drives from different production runs.  We're less likely to get 4 duds but more likely to get at least one dud.  Depending on how many production runs are bad versus good runs.. we might have a higher chance of getting 2 out of 4 duds by mixing.

 

Again.. one dead drive bad.. many dead drives unacceptable.   Here's the thing though.  From my experience.. about 16 years now.. I've found that drive models tend to be problematic more than specific production runs.   For example.. Seagate Barracudas from the past few years are just bad drives.  It's not that one out of a dozen production runs are bad.. they're all bad drives.   That's even more true with the WD Greens.  We bought a lot of them when they came out.. I don't think any of them are still running.. and some were replaced on warranty and those also failed.

That all doesn't necessarily argue against mixing batches as much as it argues that it's not a placebo.   

A better argument mixing is that.. for the same reasons you want to have identical model drives in the RAID, you want to have the same firmware on the drives.  

 

 

In reality.. the truth is probably somewhere in between.. 

Use the same model drives in a RAID.  It probably doesn't hurt to get them from different production batches [mix them if you've purchased several batches of drives] but don't consider that a solution to multi-drive failure.   Update them all to the same [current] firmware when possible before building your array.

This is opinion.. but I'd say keeping a hot-spare in the device [an idle drive not integrated in to the active array] and keeping a spare replacement in the drawer are far better policy than going through the trouble of trying to source a bunch of identical drives from different production runs.

post #34 of 34
Quote:
Originally Posted by fffakr View Post

Definitely use the same Make and Model.  You want the members of the Array to all have the same performance characteristics.  When you're taking a stream of data, breaking it up, and writing it across multiple disks, you don't want to have 1 member with slower write speeds than the others.  

You can make an argument either way on batch.


Thank you for your elaborative post and expertise in this area. I appreciate your insight and will remember this post when replacing disks in my MP.
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