Repositioning of tape

HP LTO 4 Tape Media
HP LTO 4 Tape Media
In my past life, I worked for a dominant tape vendor. Over the years, we had heard a number of times that tape was dead. But it never happened. BTW, it’s also not happening today.

Just a couple of weeks ago, I was at SNW and vendor friend of mine asked if I knew anyone with tape library expertise because they were bidding on more and more tape archive opportunities. Tape seems alive and kicking for what I can see.

However, the fact is that tape use is being repositioned. Tape is no longer the direct target for backups that it once was. Most backup packages nowadays backup to disk and then later, if at all, migrate this data to tape (D2D2T). Tape is being relegated to a third tier of storage, a long-term archive and/or a long term backup repository.

The economics of tape are not hard to understand. You pay for robotics, media and drives. Tape, just like any removable media requires no additional power once it’s removed from the transport/drive used to write it. Removable media can be transported to an offsite repository or accross the continent. There it can await recall with nary an ounce (volt) of power consumed.

Problems with tape

So what’s wrong with tape, why aren’t more shops using it. Let me count the problems

  1. Tape, without robotics, requires manual intervention
  2. Tape, because of its transportability, can be lost or stolen, leading to data security breaches
  3. Tape processing, in general, is more error prone than disk. Tape can have media and drive errors which cause data transfer operations to fail
  4. Tape is accessed sequentially, it cannot be randomly accessed (quickly) and only one stream of data can be accepted per drive
  5. Much of a tape volume is wasted, never written space
  6. Tape technology doesn’t stay around forever, eventually causing data obsolescence
  7. Tape media doesn’t last forever, causing media loss and potentially data loss

Likely some other issues with tape missed here, but these seem the major ones from my perspective.

It’s no surprise that most of these problems are addressed or mitigated in one form or another by the major tape vendors, software suppliers and others interested in continuing tape technology.

Robotics can answer the manual intervention, if you can afford it. Tape encryption deals effectively with stolen tapes, but requires key management somewhere. Many applications exist today to help predict when media will go bad or transports need servicing. Tape data, is and always will be, accessed sequentially, but then so is lot’s of other data in today’s IT shops. Tape transports are most definitely single threaded but sophisticated applications can intersperse multiple streams of data onto that single tape. Tape volume stacking is old technology, not necessarily easy to deploy outside of some sort of VTL front-end, but is available. Drive and media technology obsolescence will never go away, but this indicates a healthy tape market place.

Future of tape

Say what you will about Ultrium or the Linear Tape-Open (LTO) technology, made up of HP, IBM, and Quantum research partners, but it has solidified/consolidated the mid-range tape technology. Is it as advanced as it could be, or pushing to open new markets – probably not. But they are advancing tape technology providing higher capacity, higher performance and more functionality over recent generations. And they have not stopped, Ultrium’s roadmap shows LTO-6 right after LTO-5 and delivery of LTO-5 at 1.6TB uncompressed capacity tape, is right around the corner.

Also IBM and Sun continue to advance their own proprietary tape technology. Yes, some groups have moved away from their own tape formats but that’s alright and reflects the repositioning that’s happening in the tape marketplace.

As for the future, I was at an IEEE magnetics meeting a couple of years back and the leader said that tape technology was always a decade behind disk technology. So the disk recording heads/media in use today will likely see some application to tape technology in about 10 years. As such, as long as disk technology advances, tape will come out with similar capabilities sometime later.

Still, it’s somewhat surprising that tape is able to provide so much volumetric density with decade old disk technology, but that’s the way tape works. Packing a ribbon of media around a hub, can provide a lot more volumetric storage density than a platter of media using similar recording technology.

In the end, tape has a future to exploit if vendors continue to push its technology. As a long term archive storage, it’s hard to beat its economics. As a backup target it may be less viable. Nonetheless, it still has a significant install base which turns over very slowly, given the sunk costs in media, drives and robotics.

Full disclosure: I have no active contracts with LTO or any of the other tape groups mentioned in this post.

Today's data and the 1000 year archive

Untitled (picture of a keypunch machine) by Marcin Wichary (cc) (from flickr)
Untitled (picture of a keypunch machine) by Marcin Wichary (cc) (from flickr)

Somewhere in my basement I have card boxes dating back to the 1970s and paper tape canisters dating back to the 1960s with basic, 360-assembly, COBOL, PL/1 programs on them. These could be reconstructed if needed, by reading the Hollerith encoding and typing them out into text files. Finding a compiler/assembler/interpreter to interpret and execute them is another matter. But, just knowing the logic may suffice to translate them into another readily compilable language of today. Hollerith is a data card format which is well known and well described. But what of the data being created today. How will we be able to read such data in 50 years let alone 500? That is the problem.

Vista de la Biblioteca Vasconcelos by Eneas (cc) (from flickr)
Vista de la Biblioteca Vasconcelos by Eneas (cc) (from flickr)

Civilization needs to come up with some way to keep information around for 1000 years or more. There are books relevant today (besides the Bible, Koran, and other sacred texts) that would alter the world as we know it if they were unable to be read 900 years ago. No doubt, data or information like this, being created today will survive to posterity, by virtue of its recognized importance to the world. But there are a few problems with this viewpoint:

  • Not all documents/books/information are recognized as important during their lifetime of readability
  • Some important information is actively suppressed and may never be published during a regime’s lifetime
  • Even seemingly “unimportant information” may have significance to future generations

From my perspective, knowing what’s important to the future needs to be left to future generations to decide.

Formats are the problem

Consider my blog posts, WordPress creates MySQL database entries for blog posts. Imagine deciphering MySQL database entries, 500 or 1000 years in the future and the problem becomes obvious. Of course, WordPress is open source, so this information could conceivable be readily interpretable by reading it’s source code.

I have written before about the forms that such long lived files can take but for now consider that some form of digital representation of a file (magnetic, optical, paper, etc.) can be constructed that lasts a millennia. Some data forms are easier to read than others (e.g., paper) but even paper can be encoded with bar codes that would be difficult to decipher without a key to their format.

The real problem becomes file or artifact formats. Who or what in 1000 years will be able to render a Jpeg file, able to display an old MS/Word file of 1995, or be able to read a WordPerfect file from 1985. Okay, a Jpeg is probably a bad example as it’s a standard format but, older Word and WordPerfect file formats constitute a lot of information today. Although there may be programs available to read them today, the likelihood that they will continue to do so in 50, let alone 500 years, is pretty slim.

The problem is that as applications evolve, from one version to another, formats change and developers have negative incentive to publicize these new file formats. Few developers today wants to supply competitors with easy access to convert files to a competitive format. Hence, as developers or applications go out of business, formats cease to be readable or convertable into anything that could be deciphered 50 years hence.

Solutions to disappearing formats

What’s missing, in my view, is a file format repository. Such a repository could be maintained by an adjunct of national patent trade offices (nPTOs). Just like todays patents, file formats once published, could be available for all to see, in multiple databases or print outs. Corporations or other entities that create applications with new file formats would be required to register their new file format with the local nPTO. Such a format description would be kept confidential as long as that application or its descendants continued to support that format or copyright time frames, whichever came first.

The form that a file format could take could be the subject of standards activities but in the mean time, anything that explains the various fields, records, and logical organization of a format, in a text file, would be a step in the right direction.

This brings up another viable solution to this problem – self defining file formats. Applications that use native XML as their file format essentially create a self defining file format. Such a file format could be potentially understood by any XML parser. And XML format, as a defined standard, are wide enough defined that they could conceivable be available to archivists of the year 3000. So I applaud Microsoft for using XML for their latest generation of Office file formats. Others, please take up the cause.

If such repositories existed today, people in the year 3010 could still be reading my blog entries and wonder why I wrote them…

The future of libraries

Vista de la Biblioteca Vasconcelos by Eneas (cc) (from flickr)
Vista de la Biblioteca Vasconcelos by Eneas (cc) (from flickr)
My recent post on an exabyte-a-day generated a comment that got me thinking. What we need in the world today is a universal deduped archive. Such an archive would be a repository for all information generated by the world, nation, state, etc. and would automatically deduplicate the data and back it up.

Such an archive could be a new form of the current library. Keeping data for future generations and also for a nation’s population. Data held in the library repository would need to have:

  • Iron-clad data security via some form of data-at-rest encryption. This is a bit tricky since we would want to dedupe all the data from everywhere yet at the same time have the data be encrypted.
  • Enforceable digital rights management that would allow authorized users data access but unauthorized users would be restricted from viewing the information
  • Easy accessibility that would allow home consumers access to their data in an “always on” type of environment or access from any internet enabled location.
  • Dependable backups that would allow user restore of data.
  • Time limited protection scheme that after so many years (60 or 100) of data non-access/non-modification, the data would revert to public access/non-secured access for future research.
  • Government funding akin to today’s libraries that are publicly funded but serve those consumers that take the time to access their library facilities.

I see this as another outgrowth of current libraries which supports a repository for todays books, magazines, media, maps, and other published artifacts. However, in this case most data would not be published during a person’s lifetime but would become public property sometime after that person dies.

Benefits to society and the individual

Of what use could such a data repository be? Once the data becomes publicly accessible:

  • Future historians could find out what life was really like, in a detail never before available. Find out what people were watching/listening to, who people wrote to/conversed with, and what people cared about in the 21st century by perusing the data feeds of that generation.
  • Future scientists could mine the data for insights into a generation, network links, and personal data consumption.
  • Future governments could mine the data looking for what people thought about a nation, its economy, politics, etc., to help create better government.

But mostly, we don’t know what future researchers could do with the data. If such a repository existed today for what people were thinking and doing 60 to 100 years ago, history would be much more person derived rather than media derived. Economists would have a much more accurate picture of the great depression’s affect on humankind. Medicine would have a much better picture of how the pollutants and lifestyles of yesterday impact the health of today.

Also, as more and more of society’s activity involve data, the detail available on a person’s life becomes even more pervasive. Consider medical imaging, if you had a repository for a person’s x-rays from birth to death, this data could potentially be invaluable to the medicine of tomorrow.

While the data is still protected people

  • Would have a secure repository to store all their data, accessible from any internet enabled location
  • Would have an unlimited repository for their data storage not unlike timemachine on the Mac which they could go back to at anytime in the past to retrieve data.
  • Would have the potential to record even more information about their daily activities.
  • Would have a way to license their data feeds to researchers for a price sort of like registering for Nielsen TV or Alexa web tracking.

Costs to society

The price society would pay could be minimized by appropriate storage and systems technology. If in reality the data created by individuals (~87PB/day from the above mentioned post) could be deduped by a factor of 50X, this would account for only 1.7PB of unique data per day worldwide. If I take a nation’s portion of world GDP as a surrogate for data created by a nation, then for the US with 23.6% of the world’s ’08 GDP, creates ~0.4PB of individual deduped data per day or ~150PB of data per year.

Of course this would be split up by state or by municipality so the load on any one juristiction would be considerably smaller than this. But storing 150PB of data today would take 75K-2TB drives and would cost about ~$15.8M in drive costs (2TB WD drive costs $210 on Amazon) in the US. This does not account for servers, backups, power, cooling, floorspace, administration, etc but let’s triple this to incorporate these other costs. So to store all the data created by individuals in the US in 2009 would cost around $47.4M today with today’s technology.

Also consider that this cost is being cut in half every 18 to 24 months but counteracting that trend is a significant growth in data created/stored by individuals each year (~50%). Hence, by my calculations, the cost to store all this data is declining slightly every year depending on the speed of density increase and average individual data growth rate.

In any event, $47.4M is not a lot to spend to keep a nation’s worth of individual data. The benefits to today’s society would be considerable and future generations would have a treasure trove of data to analyze whenever the need presented itself.

Holding this back today is the obvious cost but also all of the data security considerations. I believe the costs are manageable, at least at the state or municipal level. As for the data security considerations, simple data-at-rest encryption is one viable solution. Although how to encrypt while still providing deduplication is a serious problem to be overcome. Enforceable digital rights, time limited protection, and the other technological features could come with time.

An Exabyte-a-day

snp microarray data by mararie (cc) (from flickr)
snp microarray data by mararie (cc) (from flickr)

At HPTechDay this week Jim Pownell, office of CTO, HP StorageWorks Division, reported on an IDC study that said this year the world is creating about an Exabyte of data each day.  An Exabyte (XB) is 10**18 bytes or 1000 PB of data.  Seems a bit high from my perspective.

Data creation by individuals

Population Growth and Income Level Chart by mattlemmon (cc) (from flickr)
Population Growth and Income Level Chart by mattlemmon (cc) (from flickr)

The US Census bureau estimates todays worldwide population at around 6.8 Billion people. Given that estimate, the XB/day number says that the average person is creating about 150MB/day.

Now I don’t know about you but we probably create that much data during our best week. That being said our family average over the last 3.5 years is more like 30.1MB/day. This average, over the last year, has been closer to 75.1MB/day (darn new digital camera).

If I take our 75.1 MB/day as a reasonable approximate average for our family and with 2 adults in our family, this would say each adult creates ~37.6MB of data per day.

Probably about 50% of todays world wide population probably has no access to create any data whatsoever. Of the remaining 50%, maybe 33% is at an age where data creation is insignificant. All this leaves about 2.3B people actively creating data at around 37.6MB/day. This would account for about 86.5PB of data creation a day.

Naturally, I would consider myself a power data creator but

  • We are not doing much with video production which takes creates gobs of data.
  • Also, my wife retains camera rights and I only take the occasional photo with my cell phone. So I wouldn’t say we are heavy into photography.

Nonetheless, 37.6MB/day on average seems exceptionally high, even for us.

Data creation by companies

However, that XB a day also accounts for corporate data generation as well as individuals. Hoovers, a US corporate database lists about 33M companies worldwide. These are probably the biggest 33M and no doubt creating lot’s of data each day.

Given the above that individuals probably account for 86.5PB/day, that leaves about ~913.5PB/day for the Hoover’s DB of 33M companies to create. By my calculations this would say each of these companies is generating about ~27.6GB/day. No doubt there are plenty of companies out there doing this each day but the average company generates 27.6GB a day?? I don’t think so.

Ok, my count of companies could be wildly off. Perhaps the 33M companies in Hoover’s DB represent only the top 20% of companies worldwide, which means that maybe there are another 132M smaller companies out there totaling 165M companies. Now the 913.5PB/day says the average company generates ~5.5GB/day. This still seems high to me, especially considering this is an average of all 165M companies world wide.

Most analysts predict data creation is growing by over 100% per year, so that XB/day number for this year will be 2XB/day next year.

Of course I have been looking at a new HD video camera for my birthday…

Sony_HDR-TG5V_Vanity350
Sony_HDR-TG5V_Vanity350

Chart of the month: SPC-1 LRT performance results

Chart of the Month: SPC-1 LRT(tm) performance resultsThe above chart shows the top 12 LRT(tm) (least response time) results for Storage Performance Council’s SPC-1 benchmark. The vertical axis is the LRT in milliseconds (msec.) for the top benchmark runs. As can be seen the two subsystems from TMS (RamSan400 and RamSan320) dominate this category with LRTs significantly less than 2.5msec. IBM DS8300 and it’s turbo cousin come in next followed by a slew of others.

The 1msec. barrier

Aside from the blistering LRT from the TMS systems one significant item in the chart above is that the two IBM DS8300 systems crack the <1msec. barrier using rotating media. Didn’t think I would ever see the day, of course this happened 3 or more years ago. Still it’s kind of interesting that there haven’t been more vendors with subsystems that can achieve this.

LRT is probably most useful for high cache hit workloads. For these workloads the data comes directly out of cache and the only thing between a server and it’s data is subsystem IO overhead, measured here as LRT.

Encryption cheap and fast?

The other interesting tidbit from the chart is that the DS5300 with full drive encryption (FDE), (drives which I believe come from Seagate) cracks into the top 12 at 1.8msec exactly equivalent with the IBM DS5300 without FDE. Now FDE from Seagate is a hardware drive encryption capability and might not be measurable at a subsystem level. Nonetheless, it shows that having data security need not reduce performance.

What is not shown in the above chart is that adding FDE to the base subsystem only cost an additional US$10K (base DS5300 listed at US$722K and FDE version at US$732K). Seems like a small price to pay for data security which in this case is simply turn it on, generate keys, and forget it.

FDE is a hard drive feature where the drive itself encrypts all data written and decrypts all data read to from a drive and requires a subsystem supplied drive key at power on/reset. In this way the data is never in plaintext on the drive itself. If the drive were taken out of the subsystem and attached to a drive tester all one would see is ciphertext. Similar capabilities have been available in enterprise and SMB tape drives is the past but to my knowledge the IBM DS5300 FDE is the first disk storage benchmark with drive encryption.

I believe the key manager for the DS5300 FDE is integrated within the subsystem. Most shops would need a separate, standalone key manager for more extensive data security. I believe the DS5300 can also interface with an standalone (IBM) key manager. In any event, it’s still an easy and simple step towards increased data security for a data center.

The full report on the latest SPC results will be up on my website later this week but if you want to get this information earlier and receive your own copy of our newsletter – email me at SubscribeNews@SilvertonConsulting.com?Subject=Subscribe_to_Newsletter.