TEST DRIVING THE ACCUSYS A08S3-PS PCI-E RAID ARRAY
 

The world of high-performance storage for digital media has changed a lot in recent years.  For the past decade or so, you’ve had the option of USB, Firewire, and now Thunderbolt drives on the portable/ consumer side, and various forms of internal and external SATA and SAS, and on the professional side.  There is also fibre channel, and as much as it works well in direct-attached storage applications, it’s expense usually dictates that it is more often used in large SAN installations.  This is primarily due to the fact that multiple arrays can be connected to multiple workstations through a switch.  This flexibility, where a fibre channel array can be used either as a direct attached volume or in an aggregated SAN volume is very appealing, but the cost-to-performance ratio of fibre channel has remained relatively high over it’s lifetime.

What if there was a way to enjoy the performance and cost effectiveness of SAS, with the flexibility of fibre channel?  A technology you may have heard of called PCI-E, widely known as the primary data interconnect inside all modern computers, is being re-envisioned as a new form of high-bandwidth storage interface in the ExaSAN line of RAID arrays from Accusys.  Essentially what Accusys has done is implemented PCI-E as a high-speed, data storage bus in place of fibre channel or SAS.  This allows an ExaSAN array to be used equally well as either a direct-attached RAID for a single workstation, or in a SAN, connected to multiple workstations at once using a PCI-E switch.  Configuration of the array itself remains as simple as a typical SAS RAID, while offering twice the bandwidth of current fibre channel storage area networks (32Gb/s vs 16Gb/s), all at a much lower cost per RAID array.

Background
Accusys has been involved with high-performance storage for quite a while, originally designing RAID controllers and management software as an OEM supplier for a number of well-known storage manufacturers.  In recent years they’ve begun designing their own brand of ExaSAN RAID arrays, and decided that instead of simply creating another “me, too” SAS or fibre channel product, they would build a new generation of devices that would make use of the rapidly increasing performance envelope of PCI-E.  In basic terms, that means an array that takes full advantage of the current crop of 150MB/s+ SAS and SATA disk drives, as well as offering lots of leg room for 500MB/s+ SSD disks before the interface itself reaches saturation.

For clarity, there have been a number of “PCI-E” storage devices introduced to market already, and as much as they also take advantage of PCI-E, there are a few important differences compared to what an Accusys ExaSAN array offers.  Namely, that those arrays were really often just a PCI-E expansion chassis modified to hold a set of disk drives and a commodity RAID card.  In fact, if you open most of them up, you will see a typical, off-the-shelf SAS RAID card connected over a SAS/SATA breakout cable similar to what you would use in a large PC workstation chassis.  These PCI-E chassis “RAID arrays” do work, but it’s important to note there is nothing innovative about their design.  They simply move the same type of SAS RAID card you normally see installed in a workstation internally, into an external enclosure.

These sorts of chassis also don’t offer the second important benefit of PCI-E, which is switchability for use in our second scenario as a storage area network volume.  An ExaSAN array on the other hand incorporates a real, thoroughbred RAID controller you’d see in a $20,000 fibre channel chassis, that can be combined with other units using the same sort of SFP-type cables and interconnects often seen in large scale supercomputing applications. This style of cabling quickly rose to prominence in supercomputing because of it’s huge bandwidth, low cost, and blazing low latency.  And now with an ExaSAN array, you can have a piece of that same technology ripping through your next editorial, color grading, or VFX session.

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ExaSAN PCI-E Host Card: Note the separate ports for DAS or SAN applications.

The ExaSAN A08S3-PS
One of the benefits of recent advances in PCI-E technology is the move to PCI-E Gen3.  This has provided a large performance improvement for the latest generation of gaming and professional graphics cards, and it offers a similar boost in performance for storage applications as well.  PCI-E Gen3, along with support for 6Gb/s SAS and SATA disks, and an updated enclosure are the headline features for the A08S3-PS.  I’ve been a long-time fan of ExaSAN’s tower form factor, and compared to many other commodity enclosures, it is extremely well built, very quiet, easy to service, and with the new cosmetic update, looks very nice in your creative bay.  Now with the addition of PCI-E Gen3, and up to (8) 4TB 6Gb/s SAS or SATA disks, you have a beautiful, high-performance enclosure that’s just as at home next to your desk, as it is in a server room connected to your SAN.

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ExaSAN A08S3-PS direct-attached to an HP z800

Performance
I’ve had the opportunity to test an A08S3 over the last few weeks with my HP z800 using applications like Autodesk Lustre, Digital Vision Nucoda, Davinci Resolve, and Adobe Premiere. If your workflow includes multiple streams of ProRes, DNxHD, or even DPX especially at UHD or 4K resolutions, you know first hand how easily a typical RAID array can be brought to it’s knees, especially as it reaches full capacity.  The thing that’s so helpful about using PCI-E as a storage interface is that the connection itself is no longer a limitation.  The drives themselves are.  This also goes for your workstation.  The HP z800 I used to test with is a 12-Core 3.47Ghz Dual Xeon with 48GB of RAM.  I will have to admit that this array is so quick, I’m now starting to see the writing on the wall for this machine as the 2011-era Nehalem motherboard simply can’t pass formats like a 4K DPX data stream as fast as the array can supply it.  With that being said, here are some popular benchmark results I obtained with the A08S3 connected to my z800.

BlackMagic Speed Test V3
Blackmagic Disk Speed Test

 

AJA System Test HD-4GB
AJA System Test: Average Read and Write

 

RAID Management and Configuration
The ExaSAN RAID management and configuration utility is called RAIDGuardX, and is comprised of a server application (deamon), and client GUI configuration tool.  It is an extremely full featured application that allows you to do any number of simple or complex operations with your ExaSAN array.  It includes complete monitoring and status for every drive, as well as chassis status, fan speed, and temperature.  Along with typical RAID configuration functions like RAID Level, Sector Size, and foreground and background initialization, it also includes more advanced options like Array Slicing, LUN mapping, Expansion, Migration, and Snapshots.  These sorts of features along with the modular power supply and RAID controller are evidence of Accusys’ long background in enterprise storage.  If you’d like a quick run through of the RAIDGuardX interface, you can take a look at the tutorial video and screenshots below.

Accusys ExaSAN Getting Started with RAIDGuardX

 

RAIDGuardX Screenshots

RadGuard-Initial
RAIDGuardX: Initial Launch with no Controller Added

 

RaidGuard-Add Controller
RAIDGuardX: A08S3-PS Controller Added and Ready to Configure

 

RaidGuard-Array Tab
RAIDGuardX: A08S3-PS RAID Array Details

 

RaidGuard-RAID Configuration
RAIDGuardX: A08S3-PS RAID Configuration Page

 

RaidGuard-Raid Options
RAIDGuardX: A08S3-PS Advanced Controller Options

 

Chassis and Enclosure
The ExaSAN tower enclosure has always been a joy to work with.  It’s beautifully built, quiet enough to have next to your desk, and easy to install and maintain.  Every important component including the drives, power supply, and RAID controller are fully modular. This means it’s easy to keep shelf spares on hand if the array is being using for critical work where downtime would be an issue.  Replacement of any component is simple enough that even non-technical personnel can perform parts replacements with little-to-no training required.

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Rear Panel of A08S3 with Modular RAID Controller, Drives, and Power Supply.

Moving From Direct-Attached to Shared Storage
Many shops will attempt to save money by simply bolting a traditional high-performance array to one of two of their better workstations to make them UHD/4K “capable”.  This may solve the problem initially, but as many of you know, having several islands of storage spread around your studio only works for so long, and one day your business will grow to the point that you’ll need a shared storage solution everyone can collaborate on.  With traditional SAS arrays, the transition to a shared storage system would mean the investment in that equipment would largely be lost, and a traditional alternative like fibre channel would mean an expensive new secondary purchase.  However, any directly-attached ExaSAN arrays can easily become shareable across all of your workstations with the addition of a ExaSAN switch, a few PCI-E host cards, and SAN filesystem software like SAN MP or FibreJet.  With just those items, you’ll quickly and easily have your storage investment working for every member of your workgroup.

Here’s how:

Configuring an Accusys ExaSAN A12S2 RAID Array in a Storage Area Network


Flexible, Fast, Affordable.
These are the three features you should be looking for in any storage system you buy today, whether it’s an SSD pocket drive, or a large rackmount chassis you’d install in your server room.  Without these three traits a storage system is offering too little, for too much.  One of the larger issues facing many of creative agencies today is how to accommodate, as well as afford, the ongoing transition to UHD/ 4K formats.  This is compounded by that fact that many customers are unwilling to necessarily pay more for something that’s seen largely as a coming industry-wide standard.

What I’ve found is that any large technology transition becomes much easier if you can break major purchases down into phases, as long as you can minimize any loses in your prior investments as you move from one phase to the next.  The Accusys ExaSAN systems fit this situation nicely, as they allow you to add high-performance storage to a few workstations that you’d like to designate for high-end editorial, VFX, or finishing work, that you can then role into a larger shared storage volume as the new high-resolution standards become more pervasive and are justified by an increased percentage of your income.

The critical factor is that any “repurchasing” of accessories or equipment that would diminish your advantage over another competing technology option has to be minimized.  Since RAID arrays are often the single most expensive component of a storage system, finding a solution that works both as direct-attached or shared volume allows you to eliminate that issue entirely.  It’s this sort of performance and flexbility that makes ExaSAN arrays a great fit for post houses and creative agencies interested in taking on high-end creative work without having to sustain a single, large hit to their balance sheet just to begin competing for it.

For more Information on the A08S3 and other ExaSAN storage arrays, visit the Accusys website here:
http://www.accusys.com.tw/products/storage/a08s3-ps-new.html