Storage at Exascale: Some Thoughts from Panasas CTO Garth Gibson

By Nicole Hemsoth

May 25, 2011

Exascale computing is not just about FLOPS. It will also require a new breed of external storage capable of feeding these exaflop beasts. Panasas co-founder and chief technology officer Garth Gibson has some ideas on how this can be accomplished and we asked him to expound on the topic in some detail.

HPCwire: What kind of storage performance will need to be delivered for exascale computing?

Garth Gibson: The top requirement for storage in an exascale supercomputer is the capability to store a checkpoint in approximately 15 minutes or less so as to keep the supercomputer busy with computational tasks most of the time. If you do a checkpoint in 15 minutes, your compute period can be as little as two and a half hours and you still spend only 10 percent of your time checkpointing. The size of the checkpoint data is determined by the memory sizing; something that some experts expect will be approximately 64 petabytes based on the power and capital costs involved. Based on that memory size, we estimate the storage system must be capable of writing at 70 terabytes per second to support a 15 minute checkpoint.

HPCwire: Given the slower performance slope of disk compared to compute, what types of hardware technologies and storage tiering will be required to provide such performance?

Gibson: While we have seen peak rates of throughput on the hundreds of gigabytes per second range today, we have to scale 1000x to get to the required write speed for exascale compute. The challenge with the 70 terabyte-per-second write requirement is that traditional disk drives will not get significantly faster over the coming decade so it will require almost 1000x the number of spindles to sustain this level of write capability.

After all, we can only write as fast as the sum of the individual disk drives. We can look at other technologies like flash storage — such as SSDs — with faster write capabilities. The challenge with this technology, however, is the huge cost delta between flash-based solutions compared to ones based on traditional hard drives. Given that the scratch space will likely be at least 10 times the size of main memory, we are looking at 640 petabytes of scratch storage which translates to over half a billion dollars of cost in flash based storage alone.

The solution is a hybrid approach where the data is initially copied to flash at 70 terabytes per second but the second layer gets 10 times as much time to write from flash to disk, lowering storage bandwidth requirements to 7 terabytes per second, and storage components to only about 100x today’s systems. You get the performance out of flash and the capacity out of spinning disk. In essence, the flash layer is really temporary “cheap memory,” possibly not part of the storage system at all, with little of no use of its non-volatility, and perhaps not using a disk interface like SATA.

HPCwire: What types of software technologies will have to be developed?

Gibson: If we solve the performance/capacity/cost issue with a hybrid model using flash as a temporary memory dump before data is written off to disk, it will require a significant amount of intelligent copy and tiering software to manage the data movement between main memory and the temporary flash memory and from there on to spinning disks. It is not even clear what layers of the application, runtime system, operating system or file system manage this flash memory.

Perhaps more challenging, there will have to be a significant amount of software investment in building reliability into the system. An exascale storage system is going to have two orders of magnitude more components than current systems. With a lot more components comes a significantly higher rate of component failure. This means more RAID reconstructions needing to rebuild bigger drives and more media failures during these reconstructions.

Exascale storage will need higher tolerance for failure as well as the capability for much faster reconstruction, such as is provided by Panasas’ parallel reconstruction, in addition to improved defense against media failures, such as is provided by Panasas’ vertical parity. And more importantly, end to end data integrity checking of stored data, data in transit, data in caches, data pushed through servers and data received at compute nodes, because there is just so much data flowing that detection of the inevitable flipped bit is going to be key. The storage industry is started on this type of high reliability feature development, but exascale computing will need exascale mechanisms years before the broader engineering marketplaces will require it.

HPCwire: How will metadata management need to evolve?

Gibson: At Carnegie Mellon University we have already seen with tests run at Oak Ridge National Laboratory that it doesn’t take a very big configuration before it starts to take thousands of seconds to open all the files, end-to-end. As you scale up the supercomputer size, the increased processor count puts tremendous pressure on your available metadata server concurrency and throughput. Frankly, this is one of the key pressure points we have right now – just simply creating, opening and deleting files can really eat into your available compute cycles. This is the base problem with metadata management.

Exascale is going to mean 100,000 to 250,000 nodes or more. With hundreds to thousands of cores per node and many threads per core — GPUs in the extreme — the number of concurrent threads in exascale computing can easily be estimated in the billions. With this level of concurrent activity, a highly distributed, scalable metadata architecture is a must, with dramatically superior performance over what any vendor offers today. While we at Panasas believe we are in a relatively good starting position, it will nevertheless require a very significant software investment to adequately address this challenge.

HPCwire: Do you believe there is a reasonable roadmap to achieve all this? Do you think the proper investments are being made?

Gibson: I believe that there is a well reasoned and understood roadmap to get from petascale to exascale. However it will take a lot more investment than is currently being put into getting to the roadmap goals. The challenge is the return on investment for vendors. When you consider that the work will take most of the time running up to 2018, when the first exascale systems will be needed, and that there will barely be more than 500 publicly known petascale computers at that time, based on TOP500.org’s historical 7-year lag on the scale of the 500th largest computer.

It is going to be hard to pay for systems development on that scale now, knowing that there is going to be only a few implementations to apportion the cost against this decade and that it will take most of the decade after that for the exascale installed base to grow to 500. We know that exascale features are a viable program at a time far enough down the line to spread the investment cost across many commercial customers such as those in the commercial sector doing work like oil exploration or design modeling.

However, in the mean time, funding a development project like exascale storage systems could sink a small company and it would be highly unattractive on the P&L of a publicly traded company. What made petascale storage systems such as Panasas and Lustre a reality was the investment that the government made with DARPA in the 1990’s and with the DOE Path Forward program this past decade. Similar programs are going to be required to make exascale a reality. The government needs to share in this investment if it wants production quality solutions to be available in the target exascale timeframe.

HPCwire: What do you think is the biggest hurdle for exascale storage?

Gibson: The principal challenge for this type of scale will be the software capability. Software that can manage these levels of concurrency, streaming at such high levels of bandwidth without bottlenecking on metadata throughput, and at the same time ensure high levels of reliability, availability, integrity, and ease-of-use, and in a package that is affordable to operate and maintain is going to require a high level of coordination and cannot come from stringing together a bunch of open-source modules. Simply getting the data path capable of going fast by hooking it together with bailing wire and duct tape is possible but it gives you a false confidence because the capital costs look good and there is a piece of software that runs for awhile and appears to do the right thing.

But in fact, having a piece of software that maintains high availability, doesn’t lose data, and has high integrity and a manageable cost of operation is way harder than many people give it credit for being. You can see this tension today in the Lustre open source file system which seems to require a non-trivial, dedicated staff trained to keep the system up and effective.

HPCwire: Will there be a new parallel file system for exascale?

Gibson: The probability of starting from scratch today and building a brand new production file system deployable in time for 2018 is just about zero. There is a huge investment in software technology required to get to exascale and we cannot get there without significant further investment in the parallel file systems available today. So if we want to hit the timeline for exascale, it is going to have to take investment in new ideas and existing implementations to hit the exascale target.

Subscribe to HPCwire's Weekly Update!

Be the most informed person in the room! Stay ahead of the tech trends with industy updates delivered to you every week!

Insights from Optimized Codes on Cineca’s Marconi

February 15, 2019

What can you do with 381,392 CPU cores? For Cineca, it means enabling computational scientists to expand a large part of the world’s body of knowledge from the nanoscale to the astronomic, from calculating quantum effe Read more…

By Ken Strandberg

What Will IBM’s AI Debater Learn from Its Loss?

February 14, 2019

The utility of IBM’s latest man-versus-machine gambit is debatable. At the very least its Project Debater got us thinking about the potential uses of artificial intelligence as a way of helping humans sift through al Read more…

By George Leopold

ClusterVision in Bankruptcy, Fate Uncertain

February 13, 2019

ClusterVision, European HPC specialists that have built and installed over 20 Top500-ranked systems in their nearly 17-year history, appear to be in the midst of bankruptcy proceedings. According to Dutch news site Drimb Read more…

By Tiffany Trader

HPE Extreme Performance Solutions

HPE Systems With Intel Omni-Path: Architected for Value and Accessible High-Performance Computing

Today’s high-performance computing (HPC) and artificial intelligence (AI) users value high performing clusters. And the higher the performance that their system can deliver, the better. Read more…

IBM Accelerated Insights

Medical Research Powered by Data

“We’re all the same, but we’re unique as well. In that uniqueness lies all of the answers….”

  • Mark Tykocinski, MD, Provost, Executive Vice President for Academic Affairs, Thomas Jefferson University

Getting the answers to what causes some people to develop diseases and not others is driving the groundbreaking medical research being conducted by the Computational Medicine Center at Thomas Jefferson University in Philadelphia. Read more…

South African Weather Service Doubles Compute and Triples Storage Capacity of Cray System

February 13, 2019

South Africa has made headlines in recent years for its commitment to HPC leadership in Africa – and now, Cray has announced another major South African HPC expansion. Cray has been awarded contracts with Eclipse Holdings Ltd. to upgrade the supercomputing system operated by the South African Weather Service (SAWS). Read more…

By Oliver Peckham

Insights from Optimized Codes on Cineca’s Marconi

February 15, 2019

What can you do with 381,392 CPU cores? For Cineca, it means enabling computational scientists to expand a large part of the world’s body of knowledge from th Read more…

By Ken Strandberg

ClusterVision in Bankruptcy, Fate Uncertain

February 13, 2019

ClusterVision, European HPC specialists that have built and installed over 20 Top500-ranked systems in their nearly 17-year history, appear to be in the midst o Read more…

By Tiffany Trader

UC Berkeley Paper Heralds Rise of Serverless Computing in the Cloud – Do You Agree?

February 13, 2019

Almost exactly ten years to the day from publishing of their widely-read, seminal paper on cloud computing, UC Berkeley researchers have issued another ambitious examination of cloud computing - Cloud Programming Simplified: A Berkeley View on Serverless Computing. The new work heralds the rise of ‘serverless computing’ as the next dominant phase of cloud computing. Read more…

By John Russell

Iowa ‘Grows Its Own’ to Fill the HPC Workforce Pipeline

February 13, 2019

The global workforce that supports advanced computing, scientific software and high-speed research networks is relatively small when you stop to consider the magnitude of the transformative discoveries it empowers. Technical conferences provide a forum where specialists convene to learn about the latest innovations and schedule face-time with colleagues from other institutions. Read more…

By Elizabeth Leake, STEM-Trek

Trump Signs Executive Order Launching U.S. AI Initiative

February 11, 2019

U.S. President Donald Trump issued an Executive Order (EO) today launching a U.S Artificial Intelligence Initiative. The new initiative - Maintaining American L Read more…

By John Russell

Celebrating Women in Science: Meet Four Women Leading the Way in HPC

February 11, 2019

One only needs to look around at virtually any CS/tech conference to realize that women are underrepresented, and that holds true of HPC. SC hosts over 13,000 H Read more…

By AJ Lauer

IBM Bets $2B Seeking 1000X AI Hardware Performance Boost

February 7, 2019

For now, AI systems are mostly machine learning-based and “narrow” – powerful as they are by today's standards, they're limited to performing a few, narro Read more…

By Doug Black

Assessing Government Shutdown’s Impact on HPC

February 6, 2019

After a 35-day federal government shutdown, the longest in U.S. history, government agencies are taking stock of the damage -- and girding for a potential secon Read more…

By Tiffany Trader

Quantum Computing Will Never Work

November 27, 2018

Amid the gush of money and enthusiastic predictions being thrown at quantum computing comes a proposed cold shower in the form of an essay by physicist Mikhail Read more…

By John Russell

Cray Unveils Shasta, Lands NERSC-9 Contract

October 30, 2018

Cray revealed today the details of its next-gen supercomputing architecture, Shasta, selected to be the next flagship system at NERSC. We've known of the code-name "Shasta" since the Argonne slice of the CORAL project was announced in 2015 and although the details of that plan have changed considerably, Cray didn't slow down its timeline for Shasta. Read more…

By Tiffany Trader

The Case Against ‘The Case Against Quantum Computing’

January 9, 2019

It’s not easy to be a physicist. Richard Feynman (basically the Jimi Hendrix of physicists) once said: “The first principle is that you must not fool yourse Read more…

By Ben Criger

AMD Sets Up for Epyc Epoch

November 16, 2018

It’s been a good two weeks, AMD’s Gary Silcott and Andy Parma told me on the last day of SC18 in Dallas at the restaurant where we met to discuss their show news and recent successes. Heck, it’s been a good year. Read more…

By Tiffany Trader

Intel Reportedly in $6B Bid for Mellanox

January 30, 2019

The latest rumors and reports around an acquisition of Mellanox focus on Intel, which has reportedly offered a $6 billion bid for the high performance interconn Read more…

By Doug Black

US Leads Supercomputing with #1, #2 Systems & Petascale Arm

November 12, 2018

The 31st Supercomputing Conference (SC) - commemorating 30 years since the first Supercomputing in 1988 - kicked off in Dallas yesterday, taking over the Kay Ba Read more…

By Tiffany Trader

Looking for Light Reading? NSF-backed ‘Comic Books’ Tackle Quantum Computing

January 28, 2019

Still baffled by quantum computing? How about turning to comic books (graphic novels for the well-read among you) for some clarity and a little humor on QC. The Read more…

By John Russell

ClusterVision in Bankruptcy, Fate Uncertain

February 13, 2019

ClusterVision, European HPC specialists that have built and installed over 20 Top500-ranked systems in their nearly 17-year history, appear to be in the midst o Read more…

By Tiffany Trader

Leading Solution Providers

SC 18 Virtual Booth Video Tour

Advania @ SC18 AMD @ SC18
ASRock Rack @ SC18
DDN Storage @ SC18
HPE @ SC18
IBM @ SC18
Lenovo @ SC18 Mellanox Technologies @ SC18
NVIDIA @ SC18
One Stop Systems @ SC18
Oracle @ SC18 Panasas @ SC18
Supermicro @ SC18 SUSE @ SC18 TYAN @ SC18
Verne Global @ SC18

Contract Signed for New Finnish Supercomputer

December 13, 2018

After the official contract signing yesterday, configuration details were made public for the new BullSequana system that the Finnish IT Center for Science (CSC Read more…

By Tiffany Trader

Deep500: ETH Researchers Introduce New Deep Learning Benchmark for HPC

February 5, 2019

ETH researchers have developed a new deep learning benchmarking environment – Deep500 – they say is “the first distributed and reproducible benchmarking s Read more…

By John Russell

IBM Quantum Update: Q System One Launch, New Collaborators, and QC Center Plans

January 10, 2019

IBM made three significant quantum computing announcements at CES this week. One was introduction of IBM Q System One; it’s really the integration of IBM’s Read more…

By John Russell

HPC Reflections and (Mostly Hopeful) Predictions

December 19, 2018

So much ‘spaghetti’ gets tossed on walls by the technology community (vendors and researchers) to see what sticks that it is often difficult to peer through Read more…

By John Russell

IBM Bets $2B Seeking 1000X AI Hardware Performance Boost

February 7, 2019

For now, AI systems are mostly machine learning-based and “narrow” – powerful as they are by today's standards, they're limited to performing a few, narro Read more…

By Doug Black

Nvidia’s Jensen Huang Delivers Vision for the New HPC

November 14, 2018

For nearly two hours on Monday at SC18, Jensen Huang, CEO of Nvidia, presented his expansive view of the future of HPC (and computing in general) as only he can do. Animated. Backstopped by a stream of data charts, product photos, and even a beautiful image of supernovae... Read more…

By John Russell

The Deep500 – Researchers Tackle an HPC Benchmark for Deep Learning

January 7, 2019

How do you know if an HPC system, particularly a larger-scale system, is well-suited for deep learning workloads? Today, that’s not an easy question to answer Read more…

By John Russell

Intel Confirms 48-Core Cascade Lake-AP for 2019

November 4, 2018

As part of the run-up to SC18, taking place in Dallas next week (Nov. 11-16), Intel is doling out info on its next-gen Cascade Lake family of Xeon processors, specifically the “Advanced Processor” version (Cascade Lake-AP), architected for high-performance computing, artificial intelligence and infrastructure-as-a-service workloads. Read more…

By Tiffany Trader

  • arrow
  • Click Here for More Headlines
  • arrow
Do NOT follow this link or you will be banned from the site!
Share This