Flash Memory Summit 2014

by Robin Harris on Sunday, 20 July, 2014

The entire StorageMojo analyst team will be saddling up and leaving the bone-dry high desert of Arizona to see the fleshpots of Santa Clara for the 2014 Flash Memory Summit. StorageMojo’s Chief Analyst will be chairing Session U-2: Annual Update on Enterprise Flash Storage. That’s on Tuesday, August 5th, at 9:45.

Who knows, maybe there will be discussion of the latency vs data services controversy.

Looking forward to meeting the attendee from the Republic of San Marino, and finding out what they’ve been doing with flash.

Don’t be shy. Feel free to sidle up and say howdy. Since California’s gun laws are stricter than Arizona’s – any gun law would be stricter – some of the boys may be feeling a bit naked. But as long as you don’t look like a rattlesnake they’ll get over it.

The StorageMojo take
If you want product announcements and demos, go to VWworld. But if you want to know what’s happening behind the scenes in the industry, Flash Memory Summit is the place to be.

Courteous comments welcome, of course.


The new storage industry rave

by Robin Harris on Thursday, 17 July, 2014

It used to be so simple: EMC, NetApp, Hitachi and the captive storage businesses of systems companies. Add in some fast running startups, such as today’s Nimble, Nutanix and Avere, to keep things interesting.

But no more. While the startups will require several more years before they make a dent in the big boy’s businesses, the cloud storage vendors are taking the joy out of high-end storage.

But wait, there’s more!
A group of new entrants are moving into the enterprise storage business and they promise to be even more exciting. Why? Because they are already large businesses with other revenue streams that can support an attack on entrenched competitors.

It’s called competition, grasshopper.
SanDisk, Western Digital and Seagate are all moving into the enterprise storage business. Then of course, there is the dark horse: Cisco.

To get a sense of the scale of the struggle it’s useful to compare EMC and NetApp to the newcomers.

EMC and their federated stovepipes have a combined market capitalization of $55 billion. And annual revenue of $23 billion.

NetApp has a current market cap of almost $12 billion based on revenue a little over $6 billion.

EMC’s growth has flatlined lately while NetApp is shrinking – and flailing.

Handicapping the race.
Western Digital and Seagate. Both have discovered the joys of high-margin storage systems. Neither is a marketing company but they do have strong brands.

10 years ago it would’ve been heresy for either company to compete with its major customers. But since its major customers are abandoning hard drives for SSDs and have no one else to buy disks from, Seagate and WD rightly figure they have nothing to lose. And they know how to play the commodity game much better than EMC.

Seagate has a $19 billion market cap on revenue of almost $14 billion. Western Digital has a market cap of $23 billion on revenue of $15 billion.

Due to the falloff in disk drive sales both companies are looking for new revenue sources and have already found success in low-end storage systems. It won’t take them long to realize they can do even better if they move up the food chain. But what to buy, since they aren’t going to build. Exablox? Panasas? Promise?

SanDisk’s market cap is $24 billion on revenue of $6.3 billion. Clearly, investors expect great things from SanDisk and their latest quarterly year-over-year revenue growth of almost 13% is part of the reason.

With their joint venture with Toshiba and their acquisition of Fusion-I/O they are well-positioned to continue to ride a market they helped invent: flash storage. Expect them to purchase an all-flash array company soon.

The Dark Horse rises
It seems inevitable that Cisco (market cap $133B; revenues $47B) will make a major move into storage: they already have servers; storage margins are excellent; and their revenue growth is slowing. They need to do something.

But what? Whiptail is a feature and not a game changer. NetApp is getting cheaper by the day, but retooling their failing product strategy would take years.

Besides, EMC has signaled, through the DSSD/Bechtolscheim acquisition, that they will take the fight to Cisco’s networking business if need be. Yet EMC holds the weaker hand: storage turmoil is greater than the network space; EMC is the smaller company; and Cisco’s market penetration is higher.

Cisco can also choose the time and place to start the fight. EMC has bigger issues.

The StorageMojo take
The fundamental dynamic is simple: the advent of commodity-based scale-out storage is killing the current high-gross margin storage business. Think the server business from 1985 to 1995.

Squeeze the gross margin dollars from 60% to 35% and something large has to give. In the mini-computer space it was Data General, Wang, Prime and DEC.

In storage?

Courteous comments welcome, of course.


Hike blog: Airport loop

by Robin Harris on Tuesday, 15 July, 2014

Walked over to the Sunset trail and thence up to Airport Mesa. This view is looking south from the east side of the mesa.


This is my favorite time of year due to the monsoon – rainy season – clouds. Probably have a thunderstorm later today. And yes, there’s an airport on top of the mesa.


Quasi-NVRAM using built-in battery backup

by Robin Harris on Monday, 14 July, 2014

Note, a version of this post appeared this morning on ZDnet.

Given that roughly a billion battery-powered computers are sold each year, you’d think that the engineers would be busy rearchitecting the storage stack to take advantage of built-in – and usually non-removable – battery backup. But no-o-o!

Recently three researchers, Hao Luo, Lei Tian and Hong Jiang of the University of Nebraska, asked why we don’t treat our mobile device DRAM as if it were nonvolatile? They designed, implemented and tested a prototype Android phone and, not surprisingly, got promising results.

Their paper, qNVRAM: quasi Non-Volatile RAM for Low Overhead Persistency Enforcement in Smartphones was presented at the latest Usenix HotStorage conference last month.

Typically Android mobile devices rely on SQLite, a shared preference key value store or filesystem APIs to save persistent data to local flash. These employ journaling or file level double writes to ensure persistency.

The motivation behind these techniques is that memory – DRAM – is volatile. Thus the multiple writes to storage, incurring substantial system overhead in devices that are already performance and power constrained.

For example, they found that more than 75% of Twitter data was being written for persistency reasons. Looking at a group of common mobile apps they found that anywhere from 37 percent to 78 percent of the data writes were for atomicity.

Here’s a graph of what they found:

Screen Shot 2014-07-14 at 2.48.07 PM

Of course, battery-backed hardware does no good if the system software is often crashing. They found that Android kernel reliability is quite good, based on bug fixes and user support calls.

They analyzed Android issue reports and found that only 10 reports or 0.05% of all 19,670 reported issues related to Android defects were unexpected or random power-off. That implies a small chance that unexpected power failure may occur.

Proto design.
The researchers constructed a prototype test system with several innovations.

Quasi-NVRAM. They set aside a portion of system DRAM to act as a battery backed up nonvolatile DRAM.
Device driver. A new device driver and library that manage I/O between the qNVRAM and system flash memory.
Persistent Page Cache. A new data structure in SQLite using quasi-NVRAM to perform in-place updates to the database files.
Relaxed data flushing. LazyFlush absorbs repeated writes to table files to further reduce I/O.

Here’s the architecture:


Implemented on an Android smartphone they found that if performed entirely in-memory,

. . . qNVRAM speeds up the insert, update and delete transactions by up to 16.33x, 15.86x and 15.76x respectively, using both.

Furthermore, the amount of data committed to flash was reduced by about 40 percent. Given how common constant feed updates are on mobile devices, this is a significant result.

The StorageMojo take
Give the many complaints about smartphones that don’t have removable batteries, you’d think someone would have looked at this before. This research shows the upside of non-removable batteries: all DRAM can be treated as NVRAM.

Of course, qNVRAM can’t replace flash. DRAM is more power-hungry and costly than flash.

But by reducing I/O overhead qNVRAM shows significant gains in performance – and presumably battery life – can be achieved at little cost. It also simplifies the problem of extending flash endurance which may have important knock-on effects – such as enabling wider use of three-level cells.

I wish the researchers had also documented the overall impact of qNVRAM on system performance and battery life. Hopefully that’s next on the list.

It was obvious five years ago that the advent of non-removable batteries on phones and notebooks suggested a clean-sheet approach to persistency mechanisms. Congratulations to the researchers for taking a rigorous look at the problem.

Courteous comments welcome, of course.


EMC buying TwinStrata to put on VMAX.

The StorageMojo take
First of all I hope Nicos and John made out like bandits. Not likely without a bidding war – I haven’t heard of one – but they did a good job building TS.

One of the attractions for EMC is that TS supports many clouds. The master of lock-in gives customers a choice when it won’t get the business anyway.

The deeper message: we can’t compete with cloud storage, so we’ve decided to make money supporting it. Expect value-added features that only work on VMAX, probably in cooperation with Google and Microsoft.

But what about the rest of the industry? It’s a good thing. EMC validation means that customers who wouldn’t consider the idea will now have to go out and look at competitors.

Six months from now cloud gateway will be on every checklist. Why not?

Thus companies who already offer gateways, like Avere, stand to gain. Their value proposition is so much more than cheaper cloud storage. If they can get a prospect to sit still for 15 minutes they have an opportunity.

No doubt about it, cloud storage is in the mainstream. In case you hadn’t heard.

Courteous comments welcome, of course. I’ve done work for TwinStrata in the past and am working on a project for them now. At least I hope I still am.

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Ch-ch-changes @StorageMojo

by Robin Harris on Wednesday, 9 July, 2014

As my 10th anniversary blogging approaches, I’ve been reconsidering the StorageMojo business model. Some changes are in order and I’d like your advice.

  • Hike blogging. The crack StorageMojo analyst team likes to go hiking and biking several times a week. Hike blogging is a picture or two that gives a flavor of the experience.
  • Sponsored posts. Despite many requests for sponsored blog posts – i.e. paid posts written by or for the sponsor – StorageMojo has resisted. But as sponsored posts, clearly labled and subject to the publisher’s editorial control, have become more common, perhaps it is time for a change.
  • Paid briefings. Vendors have been paying about $1k per head to brief IT bloggers for the last several years. There’s no obligation to blog about the briefing, but some do, as StorageMojo sometimes did. Won’t stop doing free briefings, but want to give companies the opportunity to buy attention.
  • How-to videos. StorageMojo’s most popular video is up to 375,000 views. These will be aimed at consumers, not IT pros. Continuing to do vendor videos, which are a wonderful way to get key info to people who don’t want the deep dive.
  • Refocus on emerging tech. 10 years ago object storage, flash, scale-out infrastructure and advanced erasure codes were in their infancy. Now most are mainstream. StorageMojo will focus more on cutting edge technology, products, companies and markets.

The StorageMojo take
I’d like to thank all the readers and commenters who have made StorageMojo the highest ranked (AFAIK) storage blog in the industry. These changes are intended to strengthen StorageMojo’s content and to allow me – the crack StorageMojo analyst team – to spend more time on research, conversation, reflection and writing.

But I also want your thoughts on these ch-ch-changes. They aren’t cast in concrete, so feel free to offer suggestions or concerns. Happy to keep comments private – just request it at the beginning of your comment.

Again: Courteous comments welcome, of course.


Hike blogging: July 4th, 2014

by Robin Harris on Saturday, 5 July, 2014

A new hike on July 4th. Hiked around Twin Buttes, about 7-8 miles. Heavy cloud cover heralding the start of the summer monsoon season. Finally got some sun breaking through the clouds and took this picture looking south.


Courteous comments welcome, of course. Readers, what say you on hike blogging? Like, don’t like, don’t care?


Data services more important than latency? Not!

by Robin Harris on Thursday, 3 July, 2014

Yesterday’s post on IOPS vs latency provoked some controversy on Twitter. Kappy, CTO of a midwestern IT consultancy, asserted

@storagemojo Most AFA users don’t even care about latency. Sure there are latency sensitive apps, but data services are more important.

When asked what services, Kappy said

@lleung @storagemojo standard issue stuff. Snaps, replication, deep VMware integration, rich API access, etc. See: http://t.co/7MIaaZ4eIP

I replied:

@Kappy Data services more important than performance? Really? What about the massive savings from lower latency?

Kappy replied:

@StorageMojo can you give more specifics as to what you see as “massive savings”?

The storage pyramid
Surprising question. As said in the StorageMojo post, not the tweet:

Lower latency means fewer inflight I/Os, less server I/O overhead and more server capacity. The systems can handle more work. With fewer servers, software licenses, network ports. Less power, cooling, floor space, maintenance.

Those massive savings. If flash isn’t making something better, you have to ask: Why has flash remade the storage industry in the last 10 years?

The StorageMojo take
Availability and performance are two sides of the same coin: low performance = low availability. That’s why tape’s high latency is slowly pushing it out of a market it once owned.

Most of the data services Kappy mentioned are designed to ensure availability because that’s what customers need. But the problem most data services help manage is simple: data corruption and loss.

There’s a reason we have a storage pyramid: if the cheapest storage were also the fastest that’s all we’d use. Flash has inserted itself between DRAM and disk arrays because it makes our systems perform better for a reasonable cost.

Data services are a Good Thing. But ask a customer if she’d rather have availability and performance or data services and you’ll find out quickly enough what customers care about.

Twitter isn’t the best place for a thorough airing of technical issues. But it can be educational nonetheless.

Courteous comments welcome, of course.