StorageMojo’s best papers of FAST ’13
by Robin Harris on Friday, 15 February, 2013
StorageMojo is focussed on new storage technologies, products, companies and markets. And where do new technologies come from? From people researching at the limits of the known.
That’s why StorageMojo attends the Usenix File And Storage Technology (FAST) conference every year. Top academics – many with corporate ties – and grad students present the latest research.
Many papers are submitted and reviewed before some are chosen for presentation at the conference over two and a half days. Here are StorageMojo’s favorites from FAST 13, in no particular order:
SD Codes: Erasure Codes Designed for How Storage Systems Really Fail by James S. Plank, U of Tennessee, and Mario Blaum and James L. Hafner of IBM Research. RAID systems are vulnerable to a disk failures and unrecoverable read errors, but RAID 6 is overkill for UREs. The paper investigates lighter-weight erasure codes – disk plus sector, instead of 2 disks – to reclaim capacity for user data.
The StorageMojo take: high update costs make this most attractive for active archives, not primary storage. The capacity savings could extend the economic life of current RAID strategies vs newer erasure codes.
Gecko: Contention-Oblivious Disk Arrays for Cloud Storage by Ji-Yong Shin and Hakim Weatherspoon of Cornell, Mahesh Balakrishnan of Microsoft Research and Tudor Marian of Google. The limited I/O performance of disks makes contention a persistant problem on shared systems. The authors propose a novel log structured disk/SSD configuration and show that it virtually eliminates contention between writes, reads and garbage collection.
The StorageMojo take: SSDs help with contention, but they aren’t affordable for large-scale deployments. Gecko offers a way to leverage SSDs for log-structured block storage that significantly improves performance at a reasonable hardware cost.
Write Policies for Host-side Flash Caches by Leonardo Marmol, Raju Rangaswami and Ming Zhao of Florida International U., Swaminathan Sundararaman and Nisha Talagala of Fusion-io and Ricardo Koller of FIU and VMware. Write-through caching is safe but expensive. NAND’s non-volatile nature enables novel write-back cache strategies that preserve data integrity while improving performance. Thanks to large DRAM caches, read-only flash caches aren’t the performance booster they would have been even 5 years ago.
The StorageMojo take: Using flash only for reads mean ignoring half – or more – of the I/O problem. This needs to be fixed and this paper points the way.
Understanding the Robustness of SSDs under Power Fault by Mai Zheng and Feng Qin of Ohio State and Joseph Tucek and Mark Lillibridge of HP Labs. The authors tested 15 SSDs from 5 vendors by injecting power faults. 13 of the 15 lost data that should have been written and 2 of the 13 suffered massive corruption.
The StorageMojo take: We may be trusting SSDs more than they deserve. This research points out problems with still immature SSD technology.
A Study of Linux File System Evolution by Lanyue Lu, Andrea C. Arpaci-Dusseau, Remzi H. Arpaci-Dusseau and Shan Lu of the University of Wisconsin. The authors analyzed 8 years of Linux file system patches – 5079 of them – and discovered, for instance, that
. . . semantic bugs, which require an understanding of file-system semantics to find or fix, are the dominant bug category (over 50% of all bugs). These types of bugs are vexing, as most of them are hard to detect via generic bug detection tools; more complex model checking or formal specification may be needed.
The StorageMojo take: Anyone building or maintaining a file system should read this paper to get a handle on how and why file systems fail. Tool builders will find some likely projects as well.
Courteous comments welcome, of course. There were some great posters and WIP presentations as well that I hope to write about soon.
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FAST ’13
by Robin Harris on Saturday, 9 February, 2013
The StorageMojo team has been hankering to see some bright lights and – just maybe – avoid some more mountain snow and cold. So its off to the fleshpots of Silicon Valley to see what’s been cooked up at the File And Storage Technology ’13.
If you see someone looking like the fellow to the right, don’t be shy, come over and say “howdy!” Always looking to meet new folks.
The StorageMojo take
FAST isn’t as flashy as more commercial events, but that’s OK. There is a lot of out-of-the-box thinking by very smart people. That’s a Very Good Thing.
Courteous comments welcome, of course.
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Why virtualization is a feature and VMware will lose
by Robin Harris on Thursday, 7 February, 2013
I was asked at the SNIA nonvolatile memory conference why I did not include virtualization as a major driver for the use of nonvolatile memory. Flash helps with the multiple virtual machine I/O blender problem.
But we also had that problem when we were running multiple applications on a single machine. Yes, performance requirements were lower, but we managed.
I consider virtualization a feature and not a market. Why is virtualization a feature rather than a long-term product as many keen observers believe?
VM history
In the 1970s we had the virtual memory operating system wars. A number of companies, including DEC, Prime and IBM, developed virtual memory operating systems.
The key enabler of the virtual memory operating systems was the advent of 32-bit processors with true 32-bit address spaces. This is back when people programmed on minicomputers with a quarter of a megabyte to a maximum 4 MB of physical memory.
The VAX/VMS (Virtual Address eXtension/Virtual Memory System) OS, in contrast, offered a massive 4GB address space, 2 of which were reserved for the system and 2 for users.
Virtual memory operating systems enabled important changes for the industry. Software developers could focus on making their software as functional as possible without worrying about the underlying memory architecture.
The virtual memory wars continued into the PC era, when MS-DOS was limited to a 640KB address space and Quarterdeck systems came in with QEMM. But eventually Intel and Microsoft got their act together and solved the problem of virtual memory for the masses.
No one pays extra for a virtual memory operating system today. It is expected functionality that most don’t even know exists.
Like 32-bit processors the advent of microprocessors powerful enough to run multiple applications led to the virtual machine opportunity. If Microsoft had not been intent on selling as many server licenses as possible, they could have improved their multitasking so that the problem of server sprawl might never have occurred.
Be that as it may, there is nothing in today’s virtualization technology that could not and should not be incorporated into server operating systems. In 20 years new CompSci grads won’t know that virtual machines weren’t always built into the OS.
Feature vs product
Now just because something is at bottom a feature rather than a product doesn’t mean that you can’t make gobs of money before it becomes common. VMware is one example.
Data deduplication, for example, is clearly a feature. But the founders of Data Domain were able to make a lot of money by exploiting that feature with a high-quality application-focused implementation and being first to market.
Now deduplication is being built into new products. While debates over implementation details will continue among engineers, in a few years most users will see deduplication as a checkbox item.
The transient and the permanent
How do we distinguish between a feature and a product? It is the difference between the transient and the permanent.
Transient problems can be resolved. Permanent problems can only be managed.
Processor virtual memory management is a problem that has been solved for the majority of the world’s computers. Data de-duplication can be added over time to storage systems as computing power increases and the cost of bandwidth and random I/Os – thanks NVM! – drops.
But some problems can only be managed, not solved. The issues of scale, aggregation and metadata – among others – will always be with us.
Like gas-rich regions of galactic star formation, these manageable-but-not-solvable issues will continue to be areas rich in startup formation.
The StorageMojo take
Applying this theory to current markets yields some predictions:
- VMware, despite its feature-rich ecosystem and early lead, will lose to vendors, such as Microsoft and Red Hat, who can incorporate the most important virtualization features into their OS. VMware has no OS to fall back on and thus has no long-term future.
- Data Domain is a wasting asset. As others add dedup to their products, DD’s differentiation will decline along with its market value.
- Scale-out storage, like Isilon, will remain a lively market segment as the economics of disk, NVM, software, aggregation and metadata keep changing the calculus of efficient and durable storage.
- The improving economics of erasure coding will enable more efficient approaches to backup and archiving – as long as Moore’s Law continues to hold.
- System management is a permanent problem. When we get autonomic management at one level, the problem just kicks up a level with increasing scale.
Just as no one remembers the critical register and segment management skills required for 16-bit minicomputers, in a decade or so all the painfully acquired knowledge required to manage VMs will lose value as it gets built into the OS infrastructure. But there will always be new worlds to conquer.
Courteous comments welcome, of course. How would you define a feature vs a product?
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The stovepipe vs the grid
by Robin Harris on Friday, 25 January, 2013
Hewlett-Packard made a major announcement in December: their grid-based StoreServ 7000 based on 3PAR software. 3PAR has been selling enterprise-class storage for almost a decade and HP is building on that legacy with a radical take on enterprise storage.
HP calls it converged storage. The concept is simple: enterprise-class scale-out storage that is configurable to meet a wide range of application requirements. Flexible commodity hardware to mix-and-match to meet requirements, while configuring SSDs, hard drives or tape makes it easy to meet a wide range of price-performance ratios.
It is the enterprise analog of Google’s and Amazon’s cloud infrastructures whose scale, flexibility and cost are up-ending traditional IT. I’ve been looking for this from a major vendor since I wrote about the Google File System 7 years ago.
GFS breaks that model and shows us what can be done when the entire storage paradigm is rethought. Build the availability around the devices, not in them, treat the storage infrastructure as a single system, not a collection of parts, extend the file system paradigm to include much of what we now consider storage management, including virtualization, continuous data protection, load balancing and capacity management.
GFS is not the future. But it shows us what the future can be.
A choice, not an echo
The prevailing vendor model is the stovepipe: for every function within the enterprise there is a specialized product or set of products. These stovepipes are then glued together with a management layer that is supposed to manage everything from a single pane of glass – but never does.
Competition is stovepipe vs. stovepipe. The big iron arrays from EMC, Hewlett-Packard and Hitachi all compete, in theory, on availability, performance, support and cost.
The reality? Account control is often the deciding factor. Competition has stagnated over the last 10 years.
EMC is the most successful stovepipe peddler. Their technology publishing model – buy young companies that have crossed the chasm and sell the hell out of them – reduces their engineering risk at the cost of grievous incompatibility.
Storage as a layer, not a pipe
But as long as EMC can afford to buy the best – and they can – competitors are always at a disadvantage. But HP’s converged storage model changes that – just as Amazon has forever changed enterprise IT.
HP says they’ve already won 1200 customers for their converged storage line.
The StorageMojo take
No one is going to out-EMC EMC. They have the largest collection of best-of-breed point products in the industry.
Dave Donatelli, formerly of EMC, knows this well. Thus HP’s flanking move with converged storage.
Assuming HP can deliver a substantial fraction of Amazon’s benefits inside the data center, they will do very well. But the real magic will come when customers start interconnecting islands of converged storage to create a storage layer – like the network layer – in their infrastructure.
There are substantial customer political obstacles, but Amazon’s success has changed how CFOs look at IT. Smart CIOs are listening and responding.
Congratulations to HP and the 3PAR team for coming up with the only credible challenge to EMC in the last 15 years. I wish them every success.
Courteous comments welcome, of course. The friendly folks at HP flew me to Europe last year to get the announcement first hand. But I’d like a technical briefing from a 3PAR architect.
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Long-term storage at Storage Visions 2013
by Robin Harris on Friday, 18 January, 2013
No CES for me this year, but did attend Storage Visions 2013. Some cool stuff there.
Panasonic’s Blu-ray RAID archive robot
Panasonic has a Blu-ray-based storage system that looks interesting. Imagine 12 Blu-ray discs in the striped RAID configuration. The RAID gives the Blu-ray discs speed and competitive capacity.
Specs:
- 200MB/sec throughput
- 1.2TB per cartridge of 12 discs
- 108TB per archive of 90 cartridge
- 60 second access time
- 6 Watts standby, 100 Watts R/W
- 6U rackmountable box
The 12 Blu-ray discs are in a cartridge about the size of a tape. The disc unloader places them into 12 different Blu-ray drives for reading and writing.
But can Panny’s Blu-rays with a claimed 50 year life be trusted? I’d like something better.
The 1000 year DVD
That something better may be here. It is a DVD, and soon to be a Blu-ray disc, disc, with a claimed life of 1000 years.
The key is a writable layer that, unlike existing writable DVDs, uses an inorganic mineral layer to store the data. Doug Hansen, CTO, told me that they use a stone-like material.
Most rocks are silicates, oxides and metalloids. M-DISC’s material at nanoscale looks like igneous rock. Extremely thin layer and fine-grained – 100nm thick – horizontal scale 1/2 micron and smaller for bluray.
The laser burn heats the mineral layer so there’s a bit of melting and surface tension creates a hole. The material migrates to create a berm.
Because it is physically burnt into that inorganic mineral layer of the DVD media, it cannot and will not shift or change over time. The layer will last as long as the disc’s tough polycarbonate plastic. Most credible optical story I’ve heard.
Ridata is producing the discs, with Blu-ray versions expected this summer. All current LG DVD burners are warranteed to properly burn M-DISCs, which means you take your chances with other brands today.
Quotium
Quotium’s StorSentry software analyzes the quality of tape storage on a real-time runtime basis. With LTO tapes warranteed for only 200 complete read/write cycles, and costing almost as much as a disk drive, anything that can extend the useful life of a tape while protecting your data is a Good Thing.
Media Entertainment & Scientific Storage
MESS is a new group looking at long-term storage stack from media all the way to Digital Asset Management. Paul Evans, a long-time big systems guy, is heading it up.
The StorageMojo take
For some reason my attention was on the long-term storage issues that media and entertainment folks must grapple with. Given the massive carelessness of the movie industry over the last 100 years – and the loss of thousands of movies – I don’t believe that republishing all data every 5 years is a viable long-term strategy.
Long-term readability is a major problem with any digital medium. Assuming the media is good, can you count on a machine able to read it?
Optical has an important advantage because optical technology is everywhere and easy to replicate. Compare that to the specialized head/media engineering of tape – typically promising compatibility over 2-3 generations – and you’ll have a much more difficult time reading an LTO-5 tape in 20 years.
Panasonic should get together with M-DISC to produce a true long-term, high-performance storage system. But in the meantime, tape is still a major piece of the long-term storage puzzle, and Quotium’s software seems like a step in the right direction.
But MESS is correct to focus on the entire stack. Even if you can read the media, can you make sense of it?
One of these days the relentless growth in the density and speed of digital media will slow. When that happens it will become practically impossible to maintain existing data without a long-term strategy.
While we can hope that slowdown is decades away, the earlier we start thinking about it the better prepared we will be. Our digital civilization depends on it.
Courteous comments welcome, of course. Come to think of it, maybe the fact that I moderated a panel on long-term storage put me in that frame of mind. Go figure.
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2013: Year of the slog
by Robin Harris on Wednesday, 2 January, 2013
There are years where new ideas and concepts explode. And there are years of consolidation. 2013 will be the latter.
The storage industry has a lot to digest. Here are some of the issues.
ReRAM
Would-be vendors of the enterprise NAND flash replacement technology, Resistance RAM or ReRAM, will be hunting for launch customers. While their new product won’t be as cheap as NAND flash, it doesn’t need to be because enterprise customers will pay for greater speed, reliability and durability. The medium isn’t a big cost driver.
If ReRAM launches this year, who will lead the charge? I’d bet on either Intel, Violin Memory, Kaminario or Samsung. Intel and Samsung would incorporate ReRAM into their SSDs, while Kaminario and Violin would build it into their high-end solid-state arrays.
Disks
Disk drive vendors are trying to figure out how to survive the deflation of their largest market due to tablets and smart phones. They’re counting on hybrid drives that blunt the performance advantages of pure SSDs. But they’ll need a higher level of commitment to architecting the right products than I’ve seen so far.
We’ll also see if Hitachi’s helium drives can make it in the marketplace. Hitachi/WD must have a major data center launch customer – Google, Facebook or Amazon – since no major server vendor would offer them without a 2nd source.
Next-gen systems
Architects from next-gen storage companies such as Avere, Nimble Storage, Amplidata, Nimbus Data, Fusion-io, Starboard, Nutanix, Violin Memory, Tegile and many others will be tuning their systems and software – mostly software these days – based on real customer workloads instead of guesstimates.
HP’s converged storage is a special case. Will Donatelli be able to motivate HP’s enterprise sales force to move the product?
Cloud
Cloud storage and computing will continue to bend the arc of enterprise new technology adoption. CFOs will become tougher in their questioning of CIOs given the obvious CapEx advantages of cloud infrastructure.
Big Data
Multiple slogs for Big Data. Privacy concerns and regulation. The plethora of infrastructure options slows decision making and PO writing. Dawning awareness that the output is only as good as the questions you ask – technology is secondary.
But we’re only at the beginning of the Big Data revolution.
The StorageMojo take
The last decade has seen an explosion of new storage architectures and technologies. That’s as it should be, since storage is the hardest part of information infrastructure – and the most critical.
But while innovation won’t halt this year, it’s time for the market to sort things out. CIOs who value their jobs will be looking beyond their usual suppliers to better compete with cloud IaaS vendors.
It will be an interesting year.
Courteous comments welcome, of course. I’ve done work for several of the mentioned vendors, but for most I haven’t.
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EMC’s Xtreme embarrassment
by Robin Harris on Wednesday, 5 December, 2012
EMC’s Pravda, Chuck Hollis, chats in an interview about XtremIO’s problems. This quote from a Storage Newsletter interview may have some transcription errors, since SN is a French publication, but let’s not split hairs. Read it all to learn more.
When will you have a dedicated all-flash array?
We announced our XtremIO acquisition last year. We demonstrated it at VMworld and EMC World. It’s an all-flash design. Made of de-dupe, scale-out architecture, all flash. It fits very precise parts of the market.Do you sell it?
No, right now we’re in what’s called ‘early access’. Test with the customers, make sure it works right. You’ll probably see it in the first half of 2013 as a general product. It’s got a very specific profile. Random IO/s, extreme performance and tiering do not work. We have a data set where everything has to run fast.
Signal intelligence
Mr. Hollis is paid well to present the EMC party line, and he’s good at it. There are reasons for everything he says.
- Pre-announcing the new flash array is intended to freeze the market, especially Violin Memory, Kaminario, Nimbus Data and Pure Storage among others.
- “Precise parts of the market” means that EMC doesn’t want customers to see it as a Symm replacement – which given their likely Xtreme pricing and need to keep VMAX billions rolling in – is simple self-preservation.
- It won’t ship until the 2nd half of 2013 at the earliest and may slip further. But an H1/2013 announcement is likely.
Unpacking the ship date
EMC is very good at keeping secrets when they want to. In this case they don’t want to.
Why?
By telling us that they’re intending to enter the market for pure flash arrays they are hoping to slow the competitors kicking VMAX to the curb. EMC sales hates losing deals, but since they don’t have a competitive flash array they are stymied.
If the product were shippable in Q1/2013, EMC would deploy evangelists, including Mr. Hollis, to give NDA presentations, offer test lab visits, early delivery units and so on. But the “early access” program – “test with the customers, make sure it works right” – is a beta test. Normally that would come late in the development process when announce and ship dates are reasonably firm.
The dates aren’t firm if “probably” H1/2013 is the best EMC can offer. When XtremIO was bought, EMC predicted a Q1/2013 product launch.
The StorageMojo take
XtremIO hadn’t shipped a beta when EMC bought them. It’s clear that XtremIO’s “great technology” is further from a “great product” than they’d hoped.
Thus the damage control effort.
To limit embarrassment EMC may announce at EMC world in May with “planned availability” for Q3. But given the dynamics – flash arrays have a lot of interesting wrinkles – Q4 is my forecast for shipments of a de-featured product.
What went wrong? Under-estimating market demand for all-flash arrays plus over-estimating VMAX with flash cache appeal, resulting in a reluctance to pay $2B+ for a less-mature-than-they’d-like, but installed product company like Kaminario or Violin.
The year’s delay will be costly for EMC as flash array competitors become firmly entrenched in major accounts. Fixing that will take more than spin.
Courteous comments welcome, of course. I’ve done work for Kaminario and Violin, and I’m still a little peeved over EMC threatening StorageMojo.
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Nimbus Data is for real
by Robin Harris on Friday, 30 November, 2012
StorageMojo has said little about Nimbus Data, despite several briefings by CEO Thomas Isakovich over the years, due to skepticism about the company. Would you trust a company that lists one person as the management team?
But Nimbus has persevered despite StorageMojo’s inattention.
Company
Mr. Isakovich has been a fixture in the storage arena since he started TrueSAN in late 90s. Nimbus has been in business since 2006, and Tom says the company is profitable. It better be, because it has no VC funding per se, listing 3 individual investors on the management page.
One is Ed Zschau, founder of Systems Industries, a successful storage company back in the 80s that focussed on add-on storage for minicomputers. Another is Dick Watts, who led ConvergeNet to an acquisition by Dell.
Customers
Tom recently said that the company is up to 50 employees. They’ve recently installed multiple 100TB systems – which may not sound like much, but this is flash at ≈$10/GB – and they list 200 customers on their web site.
Ebay has deployed a half petabyte of Nimbus Data. At another company they beat out a NetApp filer that not only had a flash cache, but also had SSDs instead of disk drives.
Product
Nimbus started out with disk-based arrays, but has moved to all-flash media, including building their own SSDs for greater density, lower cost and higher performance. Their HALO OS supports iSCSI, SMB, NFS, Fibre Channel and Infiniband and offers replication, de-dup, encryption and snapshots.
Their newest product, Gemini promises 10 year endurance writing 1PB a week.
The StorageMojo take
While still mystified by a 1-man management “team” – who does the engineering and sales? – StorageMojo concludes that Tom has built a real company based on successful products and several unique decisions:
- No VC funding – which Violin Memory has also avoided – is today a more common option since startup costs are so much lower than a decade ago. The big advantage is that you avoid the overhead of dealing with VC investors and having to deal with their business needs.
- Building their own SSDs and array packaging. That flies in the face of the “volume begets lower costs” mantra of Intel and Pure Storage, but it looks like Nimbus has made it work for them.
- No debt. No VC money and no debt = exceptional bootstrap startup. I don’t know what they’re doing for working capital – vendor financing? – but it seems to be working.
Nimbus Data: check ‘em out.
Courteous comments welcome, of course. Anyone using their products care to comment on your experience?
Regrettably, Nimbus Data has never paid me for any work, but they are a sponsor of Tech Field Days that brings me and other blogger/analysts on junkets to (usually) Silicon Valley.
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