Tony Pearson is a Master Inventor and Senior IT Architect for the IBM Storage product line at the
IBM Systems Client Experience Center in Tucson Arizona, and featured contributor
to IBM's developerWorks. In 2018, Tony celebrates his 32th year anniversary with IBM Storage. He is
author of the Inside System Storage series of books. This blog is for the open exchange of ideas relating to storage and storage networking hardware, software and services.
(Short URL for this blog: ibm.co/Pearson )
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Continuing my catch-up on past posts, Jon Toigo on his DrunkenData blog, posted a ["bleg"] for information aboutdeduplication. The responses come from the "who's who" of the storage industry, so I will provide IBM'sview. (Jon, as always, you have my permission to post this on your blog!)
Please provide the name of your company and the de-dupe product(s) you sell. Please summarize what you think are the key values and differentiators of your wares.
IBM offers two different forms of deduplication. The first is IBM System Storage N series disk system with Advanced Single Instance Storage (A-SIS), and the second is IBM Diligent ProtecTier software. Larry Freeman from NetApp already explains A-SIS in the [comments on Jon's post], so I will focus on the Diligent offering in this post. The key differentiators for Diligent are:
Data agnostic. Diligent does not require content-awareness, format-awareness nor identification of backup software used to send the data. No special client or agent software is required on servers sending data to an IBM Diligent deployment.
Inline processing. Diligent does not require temporarily storing data on back-end disk to post-process later.
Scalability. Up to 1PB of back-end disk managed with an in-memory dictionary.
Data Integrity. All data is diff-compared for full 100 percent integrity. No data is accidentally discarded based on assumptions about the rarity of hash collisions.
InfoPro has said that de-dupe is the number one technology that companies are seeking today — well ahead of even server or storage virtualization. Is there any appeal beyond squeezing more undifferentiated data into the storage junk drawer?
Diligent is focused on backup workloads, which has the best opportunity for deduplication benefits. The two main benefits are:
Keeping more backup data available online for fast recovery.
Mirroring the backup data to another remote location for added protection. With inline processing, only the deduplicated data is sent to the back-end disk, and this greatly reduces the amount of data sent over the wire to the remote location.
Every vendor seems to have its own secret sauce de-dupe algorithm and implementation. One, Diligent Technologies (just acquired by IBM), claims that their’s is best because it collapses two functions — de-dupe then ingest — into one inline function, achieving great throughput in the process. What should be the gating factors in selecting the right de-dupe technology?
As with any storage offering, the three gating factors are typically:
Will this meet my current business requirements?
Will this meet my future requirements for the next 3-5 years that I plan to use this solution?
What is the Total Cost of Ownership (TCO) for the next 3-5 years?
Assuming you already have backup software operational in your existing environment, it is possible to determine thenecessary ingest rate. How many "Terabytes per Hour" (TB/h) must be received, processed and stored from the backup software during the backup window. IBM intends to document its performance test results of specific software/hardwarecombinations to provide guidance to clients' purchase and planning decisions.
For post-process deployments, such as the IBM N series A-SIS feature, the "ingest rate" during the backup only has to receive and store the data, and the rest of the 24-hour period can be spent doing the post-processing to find duplicates. This might be fine now, but as your data grows, you might find your backup window growing, and that leaves less time for post-processing to catch up. IBM Diligent does the processing inline, so is unaffected by an expansion of the backup window.
IBM Diligent can scale up to 1PB of back-end data, and the ingest rate does not suffer as more data is managed.
As for TCO, post-process solutions must have additional back-end storage to temporarily hold the data until the duplicates can be found. With IBM Diligent's inline methodology, only deduplicated data is stored, so less disk space is required for the same workloads.
Despite the nuances, it seems that all block level de-dupe technology does the same thing: removes bit string patterns and substitutes a stub. Is this technically accurate or does your product do things differently?
IBM Diligent emulates a tape library, so the incoming data appears as files to be written sequentially to tape. A file is a string of bytes. Unlike block-level algorithms that divide files up into fixed chunks, IBM Diligent performs diff-compares of incoming data with existing data, and identifies ranges of bytes that duplicate what already is stored on the back-end disk. The file is then a sequence of "extents" representing either unique data or existing data. The file is represented as a sequence of pointers to these extents. An extent can vary from2KB to 16MB in size.
De-dupe is changing data. To return data to its original state (pre-de-dupe) seems to require access to the original algorithm plus stubs/pointers to bit patterns that have been removed to deflate data. If I am correct in this assumption, please explain how data recovery is accomplished if there is a disaster. Do I need to backup your wares and store them off site, or do I need another copy of your appliance or software at a recovery center?
For IBM Diligent, all of the data needed to reconstitute the data is stored on back-end disks. Assuming that all of your back-end disks are available after the disaster, either the original or mirrored copy, then you only need the IBM Diligent software to make sense of the bytes written to reconstitute the data. If the data was written by backup software, you would also need compatible backup software to recover the original data.
De-dupe changes data. Is there any possibility that this will get me into trouble with the regulators or legal eagles when I respond to a subpoena or discovery request? Does de-dupe conflict with the non-repudiation requirements of certain laws?
I am not a lawyer, and certainly there are aspects of[non-repudiation] that may or may not apply to specific cases.
What I can say is that storage is expected to return back a "bit-perfect" copy of the data that was written. Thereare laws against changing the format. For example, an original document was in Microsoft Word format, but is converted and saved instead as an Adobe PDF file. In many conversions, it would be difficult to recreate the bit-perfect copy. Certainly, it would be difficult to recreate the bit-perfect MS Word format from a PDF file. Laws in France and Germany specifically require that the original bit-perfect format be kept.
Based on that, IBM Diligent is able to return a bit-perfect copy of what was written, same as if it were written to regular disk or tape storage, because all data is diff-compared byte-for-byte with existing data.
In contrast, other solutions based on hash codes have collisions that result in presenting a completely different set of data on retrieval. If the data you are trying to store happens to have the same hash code calculation as completely different data already stored on a solution, then it might just discard the new data as "duplicate". The chance for collisions might be rare, but could be enough to put doubt in the minds of a jury. For this reason, IBM N series A-SIS, that does perform hash code calculations, will do a full byte-for-byte comparison of data to ensure that data is indeed a duplicate of an existing block stored.
Some say that de-dupe obviates the need for encryption. What do you think?
I disagree. I've been to enough [Black Hat] conferences to know that it would be possible to read thedata off the back-end disk, using a variety of forensic tools, and piece together strings of personal information,such as names, social security numbers, or bank account codes.
Currently, IBM provides encryption on real tape (both TS1120 and LTO-4 generation drives), and is working withopen industry standards bodies and disk drive module suppliers to bring similar technology to disk-based storage systems.Until then, clients concerned about encryption should consider OS-based or application-based encryption from thebackup software. IBM Tivoli Storage Manager (TSM), for example, can encrypt the data before sending it to the IBMDiligent offering, but this might reduce the number of duplicates found if different encryption keys are used.
Some say that de-duped data is inappropriate for tape backup, that data should be re-inflated prior to write to tape. Yet, one vendor is planning to enable an “NDMP-like” tape backup around his de-dupe system at the request of his customers. Is this smart?
Re-constituting the data back to the original format on tape allows the original backup software to interpret the tape data directly to recover individual files. For example, IBM TSM software can write its primary backup copies to an IBM Diligent offering onsite, and have a "copy pool" on physical tape stored at a remote location. The physical tapes can be used for recovery without any IBM Diligent software in the event of a disaster. If the IBM Diligent back-end disk images are lost, corrupted, or destroyed, IBM TSM software can point to the "copy pool" and be fully operational. Individual files or servers could be restored from just a few of these tapes.
An NDMP-like tape backup of a deduplicated back-end disk would require that all the tapes are in-tact, available, and fully restored to new back-end disk before the deduplication software could do anything. If a single cartridge fromthis set was unreadable or misplaced, it might impact the access to many TBs of data, or render the entire systemunusable.
In the case of a 1PB of back-end disk for IBM Diligent, you would be having to recover over a thousand tapes back to disk before you could recover any individual data from your backup software. Even with dozens of tape drives in parallel, could take you several days for the complete process.This represents a longer "Recovery Time Objective" (RTO) than most people are willing to accept.
Some vendors are claiming de-dupe is “green” — do you see it as such?
Certainly, "deduplicated disk" is greener than "non-deduplicated" disk, but I have argued in past posts, supportedby Analyst reports, that it is not as green as storing the same data on "non-deduplicated" physical tape.
De-dupe and VTL seem to be joined at the hip in a lot of vendor discussions: Use de-dupe to store a lot of archival data on line in less space for fast retrieval in the event of the accidental loss of files or data sets on primary storage. Are there other applications for de-duplication besides compressing data in a nearline storage repository?
Deduplication can be applied to primary data, as in the case of the IBM System Storage N series A-SIS. As Larrysuggests, MS Exchange and SharePoint could be good use cases that represent the possible savings for squeezing outduplicates. On the mainframe, many master-in/master-out tape applications could also benefit from deduplication.
I do not believe that deduplication products will run efficiently with “update in place” applications, that is high levels of random writes for non-appending updates. OLTP and Database workloads would not benefit from deduplication.
Just suggested by a reader: What do you see as the advantages/disadvantages of software based deduplication vs. hardware (chip-based) deduplication? Will this be a differentiating feature in the future… especially now that Hifn is pushing their Compression/DeDupe card to OEMs?
In general, new technologies are introduced on software first, and then as implementations mature, get hardware-based to improve performance. The same was true for RAID, compression, encryption, etc. The Hifn card does "hash code" calculations that do not benefit the current IBM Diligent implementation. Currently, IBM Diligent performsLZH compression through software, but certainly IBM could provide hardware-based compression with an integrated hardware/software offering in the future. Since IBM Diligent's inline process is so efficient, the bottleneck in performance is often the speed of the back-end disk. IBM Diligent can get improved "ingest rate" using FC instead of SATA disk.
Sorry, Jon, that it took so long to get back to you on this, but since IBM had just acquired Diligent when you posted, it took me a while to investigate and research all the answers.
He feels I was unfair to accuse EMC of "proprietary interfaces" without spelling out what I was referring to. Here arejust two, along with the whines we hear from customers that relate to them.
EMC Powerpath multipathing driver
Typical whine: "I just paid a gazillion dollars to renew my annual EMC Powerpath license, so you will have to come back in 12 months with your SVC proposal. I just can't see explaining to my boss that an SVC eliminates the need for EMC Powerpath, throwing away all the good money we just spent on it, or to explain that EMC chooses not to support SVC as one of Powerpath's many supported devices."
EMC SRDF command line interface
Typical whine: "My storage admins have written tons of scripts that all invoke EMC SRDF command line interfacesto manage my disk mirroring environment, and I would hate for them to re-write this to use IBM's (also proprietary) command line interfaces instead."
Certainly BarryB is correct that IBM still has a few remaining "proprietary" items of its own. IBM has been in business over 80 years, but it was only the last 10-15 years that IBM made a strategic shift away from proprietary and over to open standards and interfaces. The transformation to "openness" is not yet complete, but we have made great progress. Take these examples:
The System z mainframe - IBM had opened the interfaces so that both Amdahl and Fujitsu made compatible machines.Unlike Apple which forbids cloning of this nature, IBM is now the single source for mainframes because the other twocompetitors could not keep up with IBM's progress and advancements in technology.
Update: Due to legal reasons, the statements referring to Hercules and other S/390 emulators havebeen removed.
The z/OS operating system - While it is possible to run Linux on the mainframe, most people associate the z/OSoperating system with the mainframe. This was opened up with UNIX System Services to satisfy requests from variousgovernments. It is now a full-fledged UNIX operating system, recognized by the [Open Group] that certifies it as such.
As BarryB alludes, the unique interfaces for disk attachment to System z known as Count-Key-Data (CKD) was published so that both EMC and HDS can offer disk systems to compete with IBM's high-end disk offerings. Linux on System zsupports standard Fibre Channel, allowing you to attach an IBM SVC and anyone's storage. Both z/OS and Linux on System z support NAS storage, so IBM N series, NetApp, even EMC Celerra could be used in that case.
The System i itself is still proprietary, but recently IBM announced that it will now support standard block size (512 bytes) instead of the awkward 528 byte blocks that only IBM and EMC support today. That means that any storage vendor will be ableto sell disk to the System i environment.
Advanced copy services, like FlashCopy and Metro Mirror, are as proprietary as the similar offerings from EMCand HDS, with the exception that IBM has licensed them to both EMC and HDS. Thanks to cross-licensing, you can do [FlashCopy on EMC] equipment. Getting all the storage vendors to agree to open standards for these copy services is still workin progress under [SNIA], but at least people who have coded z/OS JCL batchjobs that invoke FlashCopy utilities can work the same between IBM and EMC equipment.
So for those out there who thought that my comment about EMC's proprietary interfaces in any way implied thatIBM did not have any of its own, the proverbial ["pot calling the kettle black"] so to speak, I apologize.
BarryB shows off his [PhotoShop skills] with the graphic below. I take it as a compliment to be compared to anAll-American icon of business success.
TonyP and Monopoly's Mr. Pennybags Separated at Birth?
However, BarryB meant it as a reference back to long time ago when IBMwas a monopoly of the IT industry, which according to [IBM's History], ended in 1973. In other words, IBMstopped being a monopoly before EMC ever existed as a company, and long before I started working for IBM myself.
The anti-trust lawsuit that BarryB mentions happened in 1969, which forced IBM to separate some of the software from its hardware offerings, and prevented IBM from making various acquisitions for years to follow, forcing IBM instead into technology partnerships. I'm glad that's all behind us now!
I'm glad to be back home in Tucson for a few weeks. All of these conferences kept mefrom reading up with what was going on in the blogosphere.
A few of us at IBM found it odd that EMC would announce their new Geographically Dispersed Disaster Restart (GDDR) the weekBEFORE their "EMC World" conference. Why not announce all of the stuff all at once instead at the conference?Were they worried that the admission that "Maui" software is still many months awaythat much of a negative stigma? The decision probably went something like this:
EMCer #1: GDDR is finally ready, should we announce now, or wait ONE week to make it part of the thingswe announce at EMC World?
EMCer #2: We are not announcing much at EMC World and what people really want us to talk about, Maui, wearen't delivering for a while. Why can't people understand we are company of hardware engineers, not software programmers! So, better not be associated with that quagmire at all.
EMCer #1: Yes, boss, I see your point. We'll announce this week then.
My fellow blogger and intellectual sparring partner, Barry Burke, on his Storage Anarchist blog, posted [are you wasting money on your mainframe dr solution?"] to bringup the GDDR announcement. The key difference is that IBM GDPS works withIBM, EMC and HDS equipment, being the fair-and-balanced folks that IBM clientshave come to expect, but it appears EMC GDDR works only with EMC equipment.Because GDDR does less, it also costs less. I can accept that. You get whatyou pay for. Of course, IBM does have a variety of protection levels, one probably will meet your budget and your business continuity needs.
To correct Barry's misperception, companies that buy IBM mainframe servers do have a choice.They can purchase their operating system from IBM, get their Linux or OpenSolarisfrom someone else like Red Hat or Novell, or build their own OS distribution fromreadily available open source. And unlike other servers that might require at leastone OS partition from the vendor, IBM mainframes can run 100 percent Linux.GDPS supports a mix of OS data. z/OS and Linux data can all be managed by GDPS.Companies that own mainframes know this. I can forgive the misperception from Barry,as EMC is focused on distributed servers instead, and many in their company may not have muchexposure to mainframe technology, or have ever spoken to mainframe customers.
But what almost had me fall out of my chair was this little nugget from his post:
"If you're an IBM mainframe customer, you are - by definition - IBM's profit stream."
Honestly, is there anyone out there that does not realize that IBM is a for-profitcorporation? In contrast, Barry would like his readers to believe that EMC is selling GDDR at cost, andthat EMC is a non-profit organization. While IBM has been delivering actual solutions thatour clients want, EMC continues to rumor that someday they might get around to offering something worthwhile.In the last six months, the shareholders have interpreted both strategies for what they really are,and the stock prices reflect that:
(Disclosure: I own IBM stock. I do not own EMC stock. Stock price comparisonsby Yahoo were based on publicly reported information. The colors blue and red to represent IBM and EMC, respectively, were selected by Yahoo graph-making facility. The color red does not necessarily imply EMC is losing money or having financial troubles.)
Of course, I for one would love to help Barry's dream of EMC non-profitability come true. If anyone has any suggestions how we can help EMC approach this goal, please post a comment below.
Today was a special day! IBM launched the world's first "Global Archive Solutions Center" in Guadalajara, Mexico.We had a formal "ribbon cutting", shown here were the following dignitaries (from left to right):
Eugenio Godard, IBM Guadalajara site level executive
Andy Monshaw, IBM General Manager of IBM System Storage
Cindy Grossman, IBM VP of Tape and Archive solutions
Luis Guillermo Martinez Mora, Secretary of economic development for the state of Jalisco, Mexico
José Décurnex, IBM General Manager for the country of Mexico
In the morning, we had a series of speeches from Cindy Grossman, Andy Monshaw, Eugenio Godard, and Federico Lepe (technology advisor for the governor for the state of Jalisco, Mexico).
While the hordes of press journalists, analysts and clients were taking the lab tour, we took a snap of thefront entrance. The day was packed with activity.
After the lab tour, IBMers Clod Barrera and Craig Butler presented to the analysts.
Cindy Grossman explained why IBM created a solutions center specific to archive solutions, and why wechose Guadalajara for its location.
I presented the pains and challenges companies are facing, and why they should partner with IBM forarchive solutions to address those requirements
Harley Puckett and I split the group. Harley is my colleague at the IBM Tucson ExecutiveBriefing Center who was the focal point for the various aspects of launching for the past eight months.He presented and moderated the presentations and demos to a collection of prospective clients.
That's me on the left, with Harley on the right.
I moderated a series of speakers to press and analysts. These included:
Mark LaBelle, Spectrum Health server and storage manager, and Steve Lawrence, Spectrum Health image solutions architect, presented their success story using IBM Grid Medical Archive Solution (GMAS). [Spectrum Health] manages seven hospitals and 130 service locations in Michigan, USA.
Mark Uren, ABSA technical architect, presented their success story working with IBM in deploying their Information Lifecycle Management (ILM) which includes Enterprise Content Management and archiving. Mark flew in all the way from Johannesburg, South Africa. [ABSA] is the financial services subsidiary of Barclay's serving theAfrican continent.
Jeffrey Beallor, president of [Global Data Vaulting], presented his success story as both a client and IBM Business Partner, offering backup and archiving solutions through "Software as a Service" (SaaS) business model. GlobalData Vaulting has its data centers in Canada, but provides services to clients worldwide.
We had a Q&A panel with the company representatives from Spectrum Health, ABSA, and Global Data Vaulting; followed by a Q&A panel with the collection of IBM executives to take questions from the press and analysts.Special thanks to Cyntia, Daniela, Carlos, Raul and Salvador for their help in making this a successful event!
(all three photos on this blog post taken by Mauricio, a professional photographer IBM hired for this event)
I had a great weekend, participating in this year's ["World Laughter Day"] yesterday, and preparingfor tonight's festivities, found me pulling out the various packages from "Simply Dinners" from my freezer.
A Tucson-based company, [Simply Dinners] offers an alternative to restaurant eating.My sister went there, assembled a set of freezer-proof plastic bags containingall the right ingredients based on specific recipes, and gave them to me for my birthday, and they have been sitting in my freezer ever since... until last weekend.
My sister was careful to choose items that fit my [Paleolithic Diet] that my nutritionist has me on. However, I was skepticalthat any plastic bag full of frozen groceries would be any better than anything I could assemble on my own.I did, after all, attend "chef school" and do know how to cook well. Each package was intended to be a "dinner for two" but since I am single, was two meals each for me.
So, I decided to try them out, which would also give me more room in my freezer for incoming items, and theycame out very well. The outside of each plastic bag was a label that explained all the steps required to heatthe food. Partially-cooked vegetables were wrapped in foil, and went in for the last 10 minutes of cooking the meat.The process was straightforward, and the meals were delicious, but nothing I could not have done on my own witha recipe and a trip to the grocery store.
The question is whether someone with little or no skills could achieve similar, or acceptable results. I havefriends who are limited to assembling sandwiches from luncheon meats and cheese slices, as anything involvingheat other than simply boiling water is beyond their skills.
The key difference between "cooking for yourself" and "building your own storage" is that you aren't buildingstorage for just yourself. Unless you are a one-person SMB company, you are building storage that all of youremployees and managers count on to do their jobs, and by extension your customers and stockholders count on.
Of course I had to read responses from others before jumping in with my thoughts.Dave Raffo from Storage Soup writes [Sun going down in storage],feeling this is yet another indication that Sun has lost their mind, recounting previous events that supportthat theory.EMC blogger Mark Twomey in his StorageZilla posts [When Open Isn't] felt a littlebit guilty kicking a competitor when down. EMC blogger Chuck Hollis questions the reasons peoplemight be tempted to even try this in his post [Do-it-Yourself Storage]. Here'san excerpt:
I really, really struggle with this concept, I do. Here's why:
Anything I use and get comfortable with -- well, I'm "locked in" to a certain degree. If I use a lot of storage software X; well, I'm sorta locked in, aren't I? Or, if I put my servers-as-storage on a three-year lease, I'm kind of locked in, aren't I?"
(For EMC, vendor lock-in is great when customers are using and comfortable with EMC products, and awful when they use andare comfortable with storage from someone else. But nobody who is "comfortable" with what they have ever complain about"vendor lock-in" do they? It's the ones who are growing uncomfortable and feel trapped in changing. Howinvolved a company's use of EMC's proprietary interfaces are can greatly determine the obstacles in switching toa different vendor.Of course, if you count yourself as someone growing uncomfortable with your existing storage vendor, IBM can help you fix that problem, but that is a subject for another post.)
Worried about "vendor lock-in"? Try "admin lock-in" where you must keep a storage admin around because he or shewas the one that put your storage together. I've seen several companies held hostage by their system adminsfor home-grown scripts that serve as "duct tape for the enterprise".The other issue is whether you have storage admins who have the necessary hardware and software engineering skillsto put suitable storage together. There are some very smart storage admins I know who could, and others that wouldhave a difficult time with this.
No doubt this is promising for the home office. I myself have taken several PCs that were running older versions of Windows,but not powerful enough to upgrade to Windows Vista, wiped them clean, loaded Linux, and configured them from everythingfrom simple browser workstations to full LAMP application server configurations. While this might sound easy, I am a professional hardwareand software engineer with Linux skills.I have no doubt that someone with sufficient engineering and Solaris skills could put together a storage system for home use.
One area where Sun definitely benefits from this "Open Storage" approach is to develop Solaris skills. I have no personal experience with OpenSolaris, but assume that if you learn it, you would be able to switch overto full Solaris quite easily.Today, most people have Windows, Linux and/or MacOS skills coming into the workforce, and this could be Sun's way of getting new fresh faces who understand Solaris commands to replace retiring "baby boomers". The lack of Solaris-knowledgeable admins is perhaps one reason why companies are switching to IBM AIX, Linux or Windows in theirdata center.
Certainly, IBM's strategic choice to support Linuxhas been a great success. People learn Linux on their home systems, and at school, and are able to carry those skillsto Linux running on everything from the smallest IBM blade server to IBM's biggest mainframe.
The videos on Sun for the "recipes" on how to put together various "storage configurations in ten minutes" appear simplerthan last summer's "How to hack an Apple iPhone to switch away from AT&T" procedures.