Are SSDs an invasive species?

A head assembly on a Seagate disk drive by Robert Scoble (cc) (from flickr)

A head assembly on a Seagate disk drive by Robert Scoble (cc) (from flickr)

I was reading about pythons becoming an invasive species in the Florida Everglades and that brought to mind SSDs.  The current ecological niche in data storage has rotating media as the most prolific predator with tape going on the endangered species list in many locales.

So where does SSD enter into the picture.  We have written before on SSD shipments start to take off but that was looking at the numbers from another direction. Given recent announcements it appears that in the enterprise, SSDs seem to be taking over the place formerly held by 15Krpm disk devices.  These were formerly the highest performers and most costly storage around.  But today, SSDs, as a class of storage, are easily the most costly storage and have the highest performance currently available.

The data

Seagate announced yesterday that they had shipped almost 50M disk drives last quarter up 8% from the prior quarter or ~96M drives over the past 6 months.  Now Seagate is not the only enterprise disk provider (Hitachi, Western Digital and others also supply this market) but they probably have the lion’s share.  Nonetheless, Seagate did mention that the last quarter was supply constrained and believed that the total addressible market was 160-165M disk drives.  That puts Seagate’s market share (in unit volume) at ~31% and at that rate the last 6 months total disk drive production should have been ~312M units.

In contrast, IDC reports that SSD shipments last year totaled 11m units. In both the disk and SSD cases we are not just talking enterprise class devices, the numbers include PC storage as well.  If we divide this number in half we have a comparable number of 5.5M SSDs for the last 6 months, giving SSDs less than a 2% market share (in units).

Back to the ecosystem.  In the enterprise, there are 15Krpm disks, 10Krpm disks and 7.2Krpm rotating media disks.  As speed goes down, capacity goes up.  In Seagate’s last annual report they stated that approximately 10% of the drives they manufactured were shipped to the enterprise.  Given that rate, of the 312M drives, maybe 31M were enterprise class (this probably overstates the number but usable as an upper bound).

As for SSDs, in the IDC report cited above, they mentioned two primary markets the PC and enterprise markets for SSD penetration.  In that same Seagate annual report, they said their desktop and mobile markets were around 80% of disk drives shipped.  If we use that proportion for SSDs that would say that of the 5.5M units shipped last half year, 4.4 were in the PC space and 1.1M were for the enterprise.  Given that, it would state that the enterprise class SSDs represent ~3.4% of the enterprise class disk drives shipped.  This is over 10X more than my prior estimate of SSDs being (<0.2%) of enterprise disk drives.  Reality probably lies somewhere between these two estimates.

I wrote a research report a while back which predicted that SSDs would never take off in the enterprise, I was certainly wrong then.  If these numbers are correct, capturing 10% of the enterprise disk market in little under 2 years can only mean that high-end, 15Krpm drives are losing ground faster than anticipated.  Which brings up the analogy of the invasive species.  SSDs seem to be winning a significant beach head in the enterprise market.

In the mean time, drive vendors are fighting back by moving from the 3.5″ to 2.5″ form factor, offering both 15K and 10K rpm drives.   This probably means that the 15Krpm 3.5″ drive’s days are numbered.

I made another prediction almost a decade ago that 2.5″ drives would take over the enterprise around 2005 – wrong again, but only by about 5 years or so. I got to stop making predictions, …

What is cloud storage good for?

Facebook friend carrousel by antjeverena (cc) (from flickr)
Facebook friend carrousel by antjeverena (cc) (from flickr)

Cloud storage has emerged  as a viable business service in the last couple of years, but what does cloud storage really do for the data center.  Moving data out to the cloud makes for unpredictable access times with potentially unsecured and unprotected data.  So what does the data center gain by using cloud storage?

  • Speed – it  often takes a long time (day-weeks-months) to add storage to in-house data center infrastructure.  In this case, having a cloud storage provider where one can buy additional storage by the GB/Month may make sense if one is developing/deploying new applications where speed to market is important.
  • Flexibility – data center storage is often leased or owned for long time periods.  If an application’s data storage requirements vary significantly over time then cloud storage, purchase-able or retire-able on a moments notice, may be just right.
  • Distributed data access – some applications require data to be accessible around the world.  Most cloud providers have multiple data centers throughout the world that can be used to host one’s data. Such multi-site data centers can be often be accessed much quicker than going back to a central data center.
  • Data archive – backing up data that is infrequently accessed wastes time and resources. As such, this data could easily reside in the cloud with little trouble.  References to such data would need to be redirected to one’s cloud provider but that’s about all that needs to be done.
  • Disaster recovery – disaster recovery for many data centers is very low on their priority list.  Cloud storage provides an easy, ready made solution to accessing one’s data outside the data center.  If you elect to copy all mission critical data out to the cloud on a periodic basis, then this data could theoretically be accessed anywhere, usable in many DR scenarios.

Probably some I am missing here but these will do for now.  Most cloud storage providers can provide any and all of these services.

Of course all these capabilities can be done in-house with additional onsite infrastructure, multi-site data centers, archive systems, or offsite backups.  But the question then becomes which is more economical.  Cloud providers can amortize their multi-site data centers across many customers and as such, may be able to provide these services much cheaper than could be done in-house.

Now if they could only solve that unpredictable access time, …

5 laws of unstructured data

Richard (Dick) Nafzger with Apollo data tape by Goddard Photo and Video (cc) (from flickr)
Richard (Dick) Nafzger with Apollo data tape by Goddard Photo and Video (cc) (from flickr)

All data operates under a set of laws but unstructured data suffers from these tendencies more than most of all. Although, information technology has helped us to create and manage data easier, it hasn’t done much to minimize the problems these laws produce.

As such, I introduce here my 5 laws of unstructured data in the hopes that they may help us better understand the data we create.

Law 1: Unstructured data grows 50% per year

This has been a truism in the data center for as far back as I can remember. In the data center this is driven by business transactions, new applications and new products/services. On top of all that corporate compliance often dictate that data be retained long after it’s usefulness has passed.

Nowadays, Law 1 is also true for the home user as well. Here it’s a combination of email and media. Not only are cameras moving from 6 to 9 megapixels, home video is moving to high definition and there is just a whole lot more media being created everyday. Also, now social media seems to have doubled or tripled our outreach data creation above “normal email” alone.

Law 2: Unstructured data access frequency diminishes over time

Data created today is accessed frequently during it’s first 90 days of life and then less often after that. Reasons for this decaying access pattern vary, but human memory has to play a significant part in this.

Furthermore, business transactions encounter a life cycle from initiation, to delivery and finally, to termination. During these transitions various unstructured data are created representing the transaction state. Such data may be examined at quarter end and possibly at year end but may never see the light of day after that.

Law 3: Unsearchable data is lost data

Given Law 2’s data access decay and Law 1’s data growth, unsearchable data is by definition, inaccessible data. It’s not hard to imagine how this plays out in the data center or home.

For the data center, unstructured data mostly resides in user and application directories. I am constantly amazed that it’s easier to find data out on the web than it is to find data elsewhere in the data center. Moreover, E-discovery has become a major business segment in recent years by attempting to search unstructured corporate data.

As a Mac user my home environment is searchable for any text string. However, my photo library is another matter. Finding a specific photo from a couple of years ago is a sequential perusal of iPhoto’s library and as such, is seldom done.

Law 4: Unstructured data is copied often

Over a decade ago, a company I worked with sponsored a study to see how often data is copied. The numbers we came up with were impressive. A small but significant % of data is copied often, it’s not unusual to see 6-8 copies of such data. Some of this copying occurs when final documents are passed on, some comes from teamwork and other joint collaboration as working documents are reviewed and some is just interesting information that deserves broader dissemination. As such, data copies can represent a significant portion of any data center’s storage.

I suppose data proliferation may not be as evident in the home but our home would be an exception. Each of our Macs has a copy of all email account and have copies of the best photos. In addition, with laptops and multiple desktops, most Mac’s have copies of each (adult) user’s work environment,

Law 5: Unstructured data manual classification schemes degrade over time

In the data center, one could easily classify any file data created and maintain a database of file meta-data to facilitate access to file data. But who has the discipline or spare time to update such a database whenever they create a file or document. While this may work for “official records”, the effort involved makes it unusable for everything else.

My favorite home example of this is once again, our iPhoto library with it’s manual classification system using stars, e.g., I can assign anything from 0 to 5 stars to any photo. Used to be that after each camera import, I would assign a star rating to each new photo. Nowadays, the only time I do this is once a year and as such, it’s becoming more problematic and less useful. As we take more photographs each year this becomes much more of a burden.

Not sure these 5 laws of unstructured data are mutually exclusive and completely exhaustive but it’s a start. If anyone has any ideas on how to improve my unstructured data laws, feel free to comment below. In the mean time, as for structured data laws, …

Seagate launches their Pulsar SSD

Seagate's Pulsar SSD (seagate.com)
Seagate's Pulsar SSD (seagate.com)

Today Seagate announced their new SSD offering, named the Pulsar SSD.  It uses SLC NAND technology and comes in a 2.5″ form factor at 50, 100 or 200GB capacity.  The fact that it uses a 3GB/s SATA interface seems to indicate that Seagate is going after the server market rather than the highend storage market place but different interfaces can be added over time.

Pulsar SSD performance

The main fact that makes the Pulsar interesting is the peak write rates at 25,000 4KB aligned writes per second versus a peak read rate of 30,000.  The ratio of peak reads to peak writes 30:25 represents a significant advance over prior SSDs and presumably this is through the magic of buffering.  But once we get beyond peak IO buffering sustained 128KB writes drops to 2600, 5300, or 10,500 ops/sec for the 50, 100, and 200GB drives respectively.  Kind of interesting that this drops as capacity drops and implies that adding capacity also adds parallelism. Sustained 4KB reads for the Pulsar is speced at 30,000.

In contrast, STEC’s Zeus drive is speced at 45,000 random reads and 15,000 random writes sustained and 80,000 peak reads and 40,000 peak writes.  So performance wise the Seagate Pulsar (200GB) SSD has about ~37% the peak read and ~63% the peak write performance with ~67% the sustained read with ~70% the sustained write performance of the Zeus drive.

Pulsar reliability

The other items of interest is that Seagate states a 0.44% annual failure rate (AFR), so for a 100 Pulsar drive storage subsystem one Pulsar drive will fail every 2.27 years.  Also the Pulsar bit error rate (BER) is specified at <10E16 new and <10E15 at end of life.  As far as I can tell both of these specifications are better than STEC’s specs for the Zeus drive.

Both the Zeus and Pulsar drives support a 5 year limited warranty.  But if the Pulsar is indeed a more reliable drive as indicated by their respective specifications, vendors may prefer the Pulsar as it would require less service.

All this seems to say that reliability may become a more important factor in vendor SSD selection. I suppose once you get beyond 10K read or write IOPs per drive, performance differences just don’t matter that much. But a BER of 10E14 vs 10E16 may make a significant difference to product service cost and as such, may justify changing SSD vendors much easier. Seems to be opening up a new front in the SSD wars – drive reliability

Now if they only offered 6GB/s SAS or 4GFC interfaces…

Problems solved, introduced and left unsolved by cloud storage

Cloud whisps (sic) by turtlemom4bacon (cc) (from flickr)
Cloud whisps (sic) by turtlemom4bacon (cc) (from flickr)

When I first heard about cloud storage I wondered just what exactly it was trying to solve. There are many storage problems within the IT shop nowadays days, cloud storage can solve a few of them but introduces more and leaves a few unsolved.

Storage problems solved by cloud storage

  • Dynamic capacity – storage capacity is fixed once purchased/leased. Cloud storage provides an almost infinite amount of storage for your data. One pays for this storage, in GB or TB per month increments, with added storage services (multi-site replication, high availability, etc.) at extra charge. Such capacity can be reduced or expanded at a moments notice.
  • Offsite DR – disaster recovery for many small shops is often non-existent or rudimentary at best. Using cloud storage, data can be copied to the cloud and accessed anywhere via the internet. Such data copies can easily support rudimentary DR for a primary data center outage.
  • Access anywhere – storage is typically local to the IT shop and can normally only be accessed at that location. Cloud storage can be accessed from any internet access point. Applications that are designed to operate all over the world can easily take advantage of such storage.
  • Data replication – data should be replicated for high availability. Cloud storage providers can replicate your data to multiple sites so that if one site goes down other sites can still provide service.

Storage problems introduced by the cloud

  • Variable access times – local storage access times vary from 1 and 100 milleseconds. However, accessing cloud storage can take from 100’s of milleseconds to minutes depending on network connectivity. Many applications cannot endure such variable access times.
  • Different access protocols – local storage support fairly standard access protocols like FC, iSCSI, NFS, and/or CIFS/SMB. Barring the few (but lately increasing) cloud providers that provide NFS access protocol, most cloud storage requires rewriting applications to use new protocols such as REST to store and access cloud file data.
  • Governance over data – local storage is by definition all located inside one data center. Many countries do not allow personal and/or financial data to be stored outside the country of origin. Some cloud storage providers will not guarantee that data stored in the cloud couldn’t be stored outside the country and jurisdiction of a single country.

Storage problems not solved by the cloud:

  • Data backups – data protection via some form of backup is essential. Nothing says that cloud storage providers cannot provide backup of data in the cloud but few if any provide such service. See my Are backups needed in the cloud post.
  • Data security – data security remains an ongoing problem for the local data center moving the data to the cloud just makes security more difficult. Many cloud storage providers provide rudimentary security for data stored but none seem to have integrated strong authentication and encryption services that might provide true data security.
  • Energy consumption – today’s storage consumes power and cooling. Although, cloud storage can be more efficient than onsite storage, this does not eliminate the environmental cost of storage.
  • Data longevity – data stored in the cloud can just as easily go obsolete as data stored locally.

Probably some I have missed here but these are a good start.

Storage strategic inflection points

EMC vs S&P 500 Stock price chart
EMC vs S&P 500 Stock price chart - 20 yrs from Yahoo Finance

Both EMC and Spectra Logic celebrated their 30 years in business this month and it got me to thinking. Both companies started the same time but one is a ~$14B revenue (’09 projected) behemoth and the other a relatively successful, but relatively mid-size storage company (Spectra Logic is private and does not report revenues). What’s the big difference between these two. As far as I can tell both companies have been adequately run for some time now by very smart people. Why is one two or more orders of magnitude bigger than the other – recognizing strategic inflection points is key.

So what is a strategic inflection point? Andy Grove may have coined the term and calls a strategic inflection point a point “… where the old strategic picture dissolves and gives way to the new.” In my view EMC has been more successful at recognizing storage strategic inflection points than Spectra Logic and this explains a major part of their success.

EMC’s history in brief

In listening this week to Joe Tucci’s talk at EMC Analyst Days he talked about the rather humble beginnings of EMC. It started out selling furniture and memory for mainframes (I think) but Joe said it really took off in 1991, almost 12 years after it was founded. It seems they latched onto some DRAM based SSD like storage technology and converted it to use disk as a RAID storage device in the mainframe and later open systems arena. RAID killed off the big (14″ platter) disk devices that had dominated storage at that time and once started could not be stopped. Whether by luck or smarts EMC’s push into RAID storage made them what they are today – probably a little of both.

It was interesting to see how this played out in the storage market space. RAID used smaller disks, first 8″, then 5.25″ and now 3.5″. When first introduced, manufacturing costs for the RAID storage were so low that one couldn’t help but make a profit selling against big disk devices that held 14″ platters. The more successful RAID became, the more available and reliable the smaller disks became which led to a virtuous cycle culminating in the highly reliable 3.5″ disk devices available today. Not sure Joe was at EMC at the time but if he was he would probably have called that transition between big platter disks and RAID a “strategic inflection point” in the storage industry at the time.

Most of EMC’s competitors and customers would probably say that aggressive marketing also helped propel EMC to be the top of the storage heap. I am not sure which came first, the recognition of a strategic inflection like RAID or the EMC marketing machine but, together, they gave EMC a decided advantage that re-constructed the storage industry.

Spectra Logic’s history in brief

As far as I can tell Spectra Logic has been in the backup software for a long time and later started supporting tape technology where they are well known today. Spectra Logic has disk storage systems as well but they seem better known for their tape and backup technology.

The big changes in tape technology over the past 30 years have been tape cartridges and robotics. Although tape cartridges were introduced by IBM (for the IBM 3480 in 1985), the first true tape automation was introduced by Storage Technology Corp. (with the STK 4400 in 1987). Storage Technology rode the wave of the robotics revolution throughout the late 80’s into the mid 90’s and was very successful for a time. Spectra Logic’s entry into tape robotics was sometime later (1995) but by the time they got onboard it was a very successful and mature technology.

Nonetheless, the revolution in tape technology and operations brought on by these two advances, probably held off the decline in tape for a decade or two, and yet it could not ultimately stem the tide in tape use apparent today (see my post on Repositioning of tape). Spectra Logic has recently introduced a new tape library.

Another strategic inflection point that helped EMC

Proprietary “Open” Unix systems had started to emerge in the late 80’s and early 90’s and by the mid 90’s were beginning to host most new and sophisticated applications. The FC interface also emerged in the early to mid 90’s as a replacement to HPC-HPPI technology and for awhile battled it out against SSA technology from IBM but by 1997 emerged victorious. Once FC and the follow-on higher level protocols (resulting in SAN) were available, proprietary Unix systems had the IO architecture to support any application needed by the enterprise and they both took off feeding on each other. This was yet another strategic inflection point and I am not sure if EMC was the first entry into this market but they sure were the biggest and as such, quickly emerged to dominate it. In my mind EMC’s real accelerated growth can be tied to this timeframe.

EMC’s future bets today

Again, today, EMC seems to be in the fray for the next inflection. Their latest bets are on virtualization technology in VMware, NAND-SSD storage and cloud storage. They bet large on the VMware acquisition and it’s working well for them. They were the largest company and earliest to market with NAND-SSD technology in the broad market space and seem to enjoy a commanding lead. Atmos is not the first cloud storage service out there, but once again EMC was one of the largest companies to go after this market.

One can’t help but admire a company that swings for the bleachers every time they get a chance at bat. Not every one is going out of the park but when they get ahold of one, sometimes they can change whole industries.