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Tony Pearson is not a medical doctor, and this blog does not reference any IBM product or service that is intended for use in the diagnosis, treatment, cure, prevention or monitoring of a disease or medical condition, unless otherwise specified on individual posts.
Tony Pearson is a Master Inventor and Senior Software Engineer for the IBM Storage product line at the
IBM Executive Briefing Center in Tucson Arizona, and featured contributor
to IBM's developerWorks. In 2016, Tony celebrates his 30th 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. You can also follow him on Twitter @az990tony.
(Short URL for this blog: ibm.co/Pearson
Tim Ferris started the festivities with [The Grand Illusion: The Real Tim Ferriss speaks]. He claimed that for the past year, he outsourced the writing of his blog to a writer from India, and an editor from the Philippines. Given that his post was dated March 31, and he writes frequently about the benefits of outsourcing, it appeared like a legitimate post. However, Tim fessed up the following day, claiming that it was April 1 in Japan where he wrote it.
Guy Kawasaki wrote[April Fools' Stories You Shouldn't Believe]including my favorite #12 "Ruby on Rails cited Twitter as the centerpiece of its new 'Rails Can Scale' marketing program." Speaking of Twitter, Fellow IBM blogger Alan Lepofsky from our Lotus Notes team wrote[Great, now there is Twitter Spam]. It looked like a real post, but then I realized, ... everything on Twitter is spam!
Topics like energy consumption and global warming were fodder for posts and pranks.The post[Was Earth Hour a joke again?], argued thatthe preparation of "Earth Hour" last week in effect used up more energy than the hour of this annual "lights-off event" actually saved. This reminded me of John Tierney's piece in the New York Times ["How virtuous is Ed Begley, Jr.?"] where a scientist explains that it is more "green" for the environment to drive a car short distances than to walk:
If you walk 1.5 miles, Mr. Goodall calculates, and replace those calories by drinking about a cup of milk, the greenhouse emissions connected with that milk (like methane from the dairy farm and carbon dioxide from the delivery truck) are just about equal to the emissions from a typical car making the same trip. And if there were two of you making the trip, then the car would definitely be the more planet-friendly way to go.
Wayan Vota, my buddy over at OLPCnews, writes in his post[Windows XO Child Centric Development] that the "Sugar" operating environment on the innovative Linux-based XO laptops will soon be re-named the"Windows XO Operating System", with their new motto "Windows XO: A Child-Centric Operating Platform for Learning, Expression and Exploration." The mocked up photo of an XO laptop with the Windows XO logo was excellent!
The economists from Freakonomics explain in [And While You're at it, Toss the Nickel] that it costs the US Government 1.7 cents to produce each penny. The US government loses $50 million dollars each year making pennies. Each nickel costs 10 cents to produce. This one was dated March 31, so it could actually be true. Sad, but true.
My favorite, however, was EMC blogger Barry Burke's post["5773 > c"] explaining howtheir scientists were able to reduce latency on the EMC SRDF disk replication capability:
What the de-dupe team found is that there is a hidden feature within recent generations of this chip that allow a single bit, under certain circumstances, to represent TWO bits of information.
Still, almost 34% of the total bits transferred were in fact aligned double-zeros, far more than all other bit combinations - and most importantly, these were quite frequently byte-aligned, as required by this new-found capability. Makes sense, if you think about it - most of those 32- and 64-bit integers are used to store numbers that are relatively small (years, months, days, credit charges, account balances, etc.). So that's why the team decided to use this new two-fer bit to represent "00".
Mathematically, if you can transmit 34% of the data using half as many bits, you reduce the number of bits you have to transfer in total by 17%. Which, while not necessarily earth-shattering, is nothing to be ashamed of. On top of the SRDF performance enhancements delivered in 5772 (30% reduction in latency or 2x the distance), this new enhancement adds another 17% latency improvement (or ~1.4x more distance at the same latency). Combined with 5772, SRDF/S customers could see a 50% reduction in latency. And 5773 allows SRDF/A cycle times to be set below 5 seconds (with RPQ) - this new feature adds a little headroom to maximize bandwidth efficiency for the shortest possible RPO.
Again, this looked real, until I did the math. Start with the speed of light in a vacuum of space ("c" in BarryB's title) which is roughly 300,000 kilometers per second, or put into more understandable units, 300 kilometers per millisecond. However, light travels slower through all other materials, and for fiber optic glass it is only 200 kilometers per millisecond. Sending a block of data across 100km, and then getting a response back that it arrived safely, is a total round-trip distance of 200km, so roughly 1 millisecond. However, EMC SRDF often takes two or three round-trips per write, versus IBM Metro Mirror on the IBM System Storage DS8000 which has got this down to a single round-trip. The number of round-trips has a much bigger effect on latency than EMC's double-bit data compression technique. With IBM, you only experience about 1 millisecond latency per write for every 100km distance between locations, the shortest latency in the industry.
It is good that once a year, you should be skeptical of what you read in the blogosphere, and sometimes check the facts!
In explaining the word "archive" we came up with two separate Japanese words. One was "katazukeru", and the other was "shimau". If you are clearing the dinner plates from the table after your meal, for example, it could be done for two reasons. Both words mean "to put away", but the motivation that drives this activity changes the word usage. The first reason, katazukeru, is because the table is important, you need the table to be empty or less cluttered to use it for something else, perhaps play some card game, work on arts and craft, or pay your bills. The second reason, shimau, is because the plates are important, perhaps they are your best tableware, used only for holidays or special occasions only, and you don't want to risk having them broken. As it turns out, IBM supports both senses of the word archive. We offer "space management" when the space on the table, (or disk or database), is more important, so older low-access data can be moved off to less expensive disk or tape. We also offer "data retention" where the data itself is valuable, and must be kept on WORM or non-erasable, non-rewriteable storage to meet business or government regulatory compliance.
The process of archiving your data from primary disk to alternate storage media can satisfy both motivations.
IBM offers software specifically to help with this archival process.For email archive, IBM offers [IBM CommonStore] for Lotus Domino and MicrosoftExchange. For database archive, including support for various ERP and CRM applications, IBM offers [IBM Optim] from the acquisition of Princeton Softech.
The problems occur when companies, under the excuse of simplification or consolidation, feel they can just usetheir backups as archives. They are taking daily backups of their email repositories and databases, and keepingthese for seven to ten years. But what happens when their legal e-discovery team needs to find all emails or database records related to a particular situation, an employee, client or account? Good luck! Most backupsare not indexed for this purpose, so storage admins are stuck restoring many different backups to temporary storage and combing through the files in hopes to find the right data.
Backups are intended for operational recovery of data that is lost or corrupted as a result of hardware failures, application defects, or human error. Disk mirroring or remote replication might help with hardware failures, but any logical deletion or corruption of data is immediately duplicated, so it is not a complete solution. FlashCopy or Snapshot point-in-time copies are useful to go back a short time to recover from logical failures, but since they are usually on the same hardware as the original copies, may not protect against hardware failures. And then there's tape, and while many people malign tape as a backup storage choice, 71 percent of customers send backups to tape, according to a 2007 Forrester Research report.
Backups often aren't viable unless restored to the same hardware platform, with the same operating system and application software to make sense of the ones and zeros. For this reason, people typically only keep two to five backup versions, for no more than 30 days, to support operational recovery scenarios. If you make updatesto your hardware, OS or application software, be sure to remember to take fresh new backups, as the old backupsmay no longer apply.
Archives are different. Often, these are copies that have been "hardened" or "fossilized" so that they make sense even if the original hardware, OS or application software is unavailable. They might be indexed so that they can be searched, so that you only have to retrieve exactly the data you are looking for. Finally, they are often stored with "rendering tools" that are able to display the data using your standard web browser, eliminating the need to have a fully working application environment.
Take any backup you might have from five years ago and try to retrieve the information. Can you do it? This might be a real eye-opener. You might have inherited this backup-as-also-archive approach from someone else, and are trying to figure out what to do differently that makes more sense. Call IBM, we can help.
There is a difference between improving "energy efficiency" versus reducing "power consumption".
Let's consider the average 100 watt light bulb, of which 5 watts generate the desired feature (light), and 95 percent generated as undesired waste (heat). In this case, it would be 5 percent efficient. If you delivered a new light bulb that generated 3 watts of light for only 30 watts of energy, then you would have an offering that was more energy efficient (10 percent instead of 5 percent) and use 70 percent less power (30 watts instead of 100 watts). This new "dim bulb" would not be as bright as the original, but has other desirable energy qualities.
Nearly all of the output of data center equipment results in heat.In The Raised Floor blog [It's Too Darn Hot!], Will Runyon explains how IBM researcher Bruno Michel in Zurich has developed new ways to cool chips with water shot through thousands of nozzles, much like capillaries in the human body. This is just one of many developments that are part of IBM's [Project Big Green]
But what if the desired feature is heat, and the undesired feature is light?In the case of Hasbro's toy[Easy-Bake Oven],a 100W incadescent light bulb is used to bake small cakes. This is generating 95W of desired heat, and onlywasting 5 percent as light (unused inside the oven). That makes this little toy 95 percent energy efficient, butconsumes as much energy as any other 100W light bulb lamp or fixture in your house. With manufacturing switchingfrom incadescent to compact flourescent bulbs, this toy oven may not be around much longer.
While we all joke that it is just a matter of time before our employers make us ride stationary bicycles attached to generators to power our monstrous data centers, 23-year old student Daniel Sheridan designeda see-saw for kids in Africa to play on that generates electricity for nearby schools. [Dan won the "mostinnovative product" at the Enterprise Festival].
Another approach is to improve efficiency by converting previously undesirable outcomes to desirable. Brian Bergstein has a piece in Forbes titled["Heat From Data Center to Warm a Pool"].Here's an excerpt:
"In a few cases, the heat produced by the computers is used to warm nearby offices. In what appears to be a first, the town pool in Uitikon, Switzerland, outside Zurich, will be the beneficiary of the waste heat from a data center recently built by IBM Corp. (nyse: IBM) for GIB-Services AG.
As in all data centers, air conditioners will blast the computers with chilly air - to keep the machines from exceeding their optimum temperature of around 70 degrees - and pump hot air out.
Usually, the hot air is vented outdoors and wasted. In the Uitikon center, it will flow through heat exchangers to warm water that will be pumped into the nearby pool. The town covered the cost of some of the connecting equipment but will get to use the heat for free."
I see a business opportunity here. Next to every data center lamenting about their power and cooling, build a state-of-the-art fitness center for the employees and nearby townspeople. Exercise on a stationary bicyclegenerating electricity, while your kids play on the see-saw generating electricity, and then afterwards thewhole family can take a dip in the heated swimming pool. And if the company subscribes to the notion of a Results-Oriented Work Environment [ROWE],it could encourage its employees to take "fitness" breaks throughout the day, rather than having everyone there in the early morning or late evening hours, leveling out the energy generated.
On StorageZilla, fellow blogger Mark Twomey introduces the latest entrant from EMC to the blogosphere,in his post [Polly Pearson's blog].
Although we share the same name, with the same exact spelling, I would like be the first to point out we are not related, at least as far as I know. Basing solely from her post[Welcome to my Blog - Part 1], sheis a year younger than I am, a lot better looking, majored in communications, and is not afraid to quit acrappy job for a much better job elsewhere. I on the other hand, majored in engineering, but agree wholeheartedly not to stick in a crappy situation. There is such a skills shortage out there in the IT industry,with a cap on U.S. [H-1B visas] at a paltry [65,000 this year]. If you don't like your IT job, you should be able toquit and find another one in the IT industry you are more passionate about.
On a similar theme, over at DrunkenData, Jon Toigo's latest post asks if you are[Feeling Insecure About Your Job?]ScoreLogix’s Job Security Index has fallen in the United States, with a sharp drop specifically for IT jobs. Jon points out that while it might be easy to point out that a number went up or down, it is far more difficultto explain why it did so. He gives a good piece of career advice:
Want to keep your job? Play by the rules of the front office: demonstrate the value of what you do for the company from the standpoint of cost-savings, risk reduction and process improvement. Make yourself indispensable. If they don’t appreciate you then, you need to move on. You will always be hiding in your cubical and sweating a pink slip ...
So shine bright. Be remarkable. It is not always easy to communicate your value in a technical position to cluelessnon-technical managers. Certainly, writing a blog helps. Within IBM, there are over 3500 bloggers. Most postwithin the safe confines behind the firewall, but manage to generate ideas, present valid arguments, and get theconversation rolling with the right set of people that might be difficult otherwise in a company like IBM of over350,000 employees scattered around the world. A few of us daringly blog in full public, and carry the conversationto our clients, prospects, analysts, journalists, Business Partners, and others within the IT industry.
So, Polly Pearson from EMC, although we have never met in person, I too welcome you to the blogosphere!
Well, its Tuesday, and that means more IBM announcements!!!
Let's do a quick recap of what was announced for storage:
We now support 1000GB SATA-II drives in the DS4000 series. This is available for the DS4200 model 7V, DS4700, DS4800 as well as the expansion drawers EXP420 and EX810. When I asked our marketing team why we weren't going to say "1TB" like everyone else, they thought 1000GB sounds bigger. I guess I should not have asked that on April Fool's day. For more details, see the IBM press releases for the [DS4200/EXP420and DS4700/DS4800/EXP810].
IBM announced new machine code Release 1.4a for the The IBM Virtualization Engine™ TS7700 virtual tape library for our System z mainframe customers.Various features come with this new level of machine code. See the IBM [Press Release] for more details.
Load balancing across the grid
Host control over the copy of logical volumes on a cluster by cluster basis
Option to gracefully remove an individual cluster from an existing grid
Initial-state reset for TS7700 database for cluster cleanup
Option to upgrade single-cache to dual-cache configuration
Also announced were updates to the 7214 model 1U2. Technically this is not in the IBM System Storage product line,but instead is designed specifically for our System p server line. This is a "media drawer" that allows you to havetape on one side, and optical on the other, in a single enclosure. IBM announced that you can now have DAT160 80GBdrives that is read-write compatible with DAT72 and DDS4 drives, and half-high LTO-4 drives that can read LTO-2 media, and is read-write compatible with LTO-3 media.Read the IBM [Press Release] for details.
Finally, if you are in the United States, Canada or the Carribean, there is a special discount promotionfor tape libraries purchased before June 20, 2008. This includes IBM TS3100, TS3200, TS3310 and TS3500 libraries.See the [Promotion Details] for eligibility.
IBM has added capability to the IBM TotalStorage Productivity Center for Replication. A quick review of the differentoptions for this component.
base Replication (uni-directional from primary to disaster site)
Two-site replication (bi-directional, including failover and failback)
Three-site replication (site awareness for all the copy sessions between all three sites in all situations)
Productivity Center for Replication supported all these levels for DS8000, DS6000 and ESS 800 disk models, butfor SVC it only supported FlashCopy and Metro Mirror for the uni-directional base. IBM announced version 3.4 today that has added support for SVC for Global Mirror (asynchronous disk mirroring) and bi-directional failover/failback. This supports lets you have "practice volumes" that allow IT managers to perform "disaster recovery exercises" without disrupting production workloads.
Also, for the DS8000, there is support for the new Space Efficient FlashCopy and DynamicVolume Expansion features. Here is the IBM
The Productivity Center for Replication server can run on either a Windows/Linux-x86 server or a z/OS mainframe server.The Productivity Center for Replication on System z offers all the same new support for SVC and DS8000, as well asincorporated Basic HyperSwap capability that I mentioned in my post last February[DS8000 Enhancements for the IBM System z10 EC].
Here are the IBM press releases for the TotalStorage Productivity Center for Replication on[Windows/Linux-x86and System z] servers.
I'm at a Business Partner conference today, discussing these announcements and other topics, so need to go back to those festivities.
My IBM colleague Marissa Benekos brought her hand-held video camera to [Storage Networking World] conference in Orlando, Florida.I am not there, as I had a conflict with another conference going on here in Tucson, so am relyingon Marissa to feed me information to blog about.
In this segment, she interviews "booth babe" David Bricker. I've known David a long time,and if you are there at the conference, tell him I sent you to visit him at the IBM booth.
David Bricker shows off some of the IBM System Storage product line at SNWin this YouTube video (2 minutes)
Sadly, I can't be in two places at once. SNW is a great conference to attend!
My colleague, Marissa Benekos, is on location with her video camera in Orlando, Florida for theComputerWorld [Storage Networking World] conference.
The IT specialists from the IBM booth were excited at David Bricker's debut on YouTube.Here's the rest of the gang in this [video].
Here's Andy Monshaw, General Manager of IBM System Storage and keynote speaker at this SNW event, summarizingIBM's "Information Infrastructure" strategy in 60 seconds in this [Youtube video].
This last video is Clod Barrera talking about the importance of security. Clod is an IBM Distinguished Engineerand Chief Technical Strategist for IBM System Storage product line. Here is his[Youtube video]
It looks like Marissa is having a lot of fun taking these videos at the event.More videos, as we get them, will be posted to the [IBM videos channel].
Storage Networking World conference is over, and the buzz from the analysts appears to be focused onXiotech's low-cost RAID brick (LCRB) called Intelligent Storage Element, or ISE.
(Full disclosure: I work for IBM, not Xiotech, in case there weren't enough IBM references on this blog page to remindyou of that. I am writing this piece entirely from publicly available sources of information, and notfrom any internal working relationships between IBM and Xiotech. Xiotech is a member of the IBM BladeCenteralliance and our two companies collaborate together in that regard.)
Fellow blogger Jon Toigo in his DrunkenData blog posted [I’m Humming “ISE ISE Baby” this Week] and then a follow-up post[ISE Launches]. I looked up Xiotech's SPC-1benchmark numbers for the Emprise 5000 with both 73GB and 146GB drives, and at 8,202 IOPS per TB, does not seem to be as fast as IBM SAN VolumeControllers 11,354 IOPS per TB. Xiotech offers an impressive 5 year warranty (by comparison, IBM offers up to 4 years, and EMC I think is stillonly 90 days).Jon also wrote a review in [Enterprise Systems]that goes into more detail about the ISE.
Fellow blogger Robin Harris in his StorageMojo blog posted [SNW update - Xiotech’s ISE and the dilithium solution], feeling that Xiotech should win the "Best Announcement at SNW" prize. He points to the cool video on the[Xiotech website]. In that video, they claim 91,000 IOPS.Given that it took forty(40) 73GB drives (or 4 datapacs) in the previous example to get 8,202 IOPS for 1TB usable, I am guessing the 91,000 IOPS is probably 44 datapacs (440 drives) glommed together, representing 11TB usable.The ISE design appears very similar to the "data modules" used in IBM's XIV Nextra system.
Fellow blogger Mark Twomey from EMC in his StorageZilla blog posted[Xiotech: Industry second]correctly points out that Xiotech's 520-byte block (512 bytes plus extra for added integrity) was not the firstin the industry. Mark explains that EMC CLARiiON had this since the early 1990's, and implies in the title that this must have been the first in the industry, making Xiotech an industry second. Sorry Mark, both EMC and Xiotech were late to the game. IBM had been using 520-byte blocksize on its disk since 1980 with the System/38. This system morphed to the AS/400, and the blocksize was bumped up to 522 bytes in 1990, and is now called the System i, where the blocksize was bumped up yet again to 528 bytes in 2007.
While IBM was clever to do this, it actually means fewer choices for our System i clients, being only able to chooseexternal disk systems that explicitly support these non-standard blocksize values, such as the IBM System Storage DS8000and DS6000 series. (Yes, BarryB, IBM still sells the DS6000!) The DS6000 was specifically designed with the System i and smaller System z mainframes in mind, and in that niche does very well. Fortunately, as I mentioned in my February post [Getting off the island - the new i5/OS V6R1], IBM has now used virtualization, in the form of the VIOS logical partition, to allow i5/OS systems to attach to standard 512-byte block devices, greatly expanding the storage choices for our clients.
(Side note: SNW happens twice per year, so the challenge is having something new and fresh to talk about each time. While Andy Monshaw, General Manager of IBM System Storage, highlighted some of the many emerging technologies in his keynote address, IBM shipped on many of them prior to his last appearance in October 2007: thin provisioning in the IBM System Storage N series, deduplication in the IBM System Storage N series Advanced Single Instance Storage (A-SIS) feature, and Solid State Disk (SSD) drives in the IBM BladeCenter HS21-XM models. Of course, not everyone buys IBM gear the first day it is available, and IBM is not the only vendor to offer these technologies. My point is that for many people, these are still not yet deployed in their own data center, and so they are still in the future for them. However, since these IBM deliveries happened more than six months ago, they're old news in the eyes of the SNW attendees. While those who follow IBM closely would know that, others like[Britney Spears] may not.)
Back in the 1990s, when IBM was developing the IBM SAN Volume Controller (SVC), we generically called the managed disk arrays that were being virtualized by the SVC as "low-cost RAID brick" or LCRB. The IBM DS3400 is a good example of this. However, as we learned, SVC is not just for LCRB, it adds value in front of all kinds of disk systems, including the not-so-low-cost EMC DMX and IBM DS8000 disk systems. ISE might make a reasonable back-end managed disk device for IBM SVC to virtualize. This gives you the new cool features of Xiotech's ISE, with IBM SVC's faster performance, more robust functionality and advanced copy services.
Next week, I'll be in South America in meetings with IBM Business Partners and storage sales reps.
Fellow blogger and cartoon writer Scott Adams writes in his Dilbert Blog posts about the [Monte Hall problem].Monte Hall was the host of the American game show Let's Make a Deal. Here is an excerpt:
"The set up is this. Game show host Monte Hall offers you three doors. One has a car behind it, which will be your prize if you guess that door. The other two doors have goats. In other words, you have a 1/3 chance of getting the car.
You pick a door, but before it is opened to reveal what is behind it, Monte opens one of the doors you did NOT choose, which he knows has a goat behind it. And he asks if you want to stick with your first choice or move to the other closed door. One of those two doors has a car behind it. Monte knows which one but you don’t."
Mathematically, on your initial choice of doors, you have a 1/3 chance of picking the car, and 2/3 chance ofpicking a goat. But, after you make a choice, Monte knows which door(s) have goats behind them, and selectsone that exposes the goat. If you stay with your initial choice, you still have a 1/3 chance that you win acar, but if you change your mind and choose the other door, your odds double, you have a 2/3 chance of winning.This is not obvious at all to most people, so Scott points people to the [Wikipedia entry] that provides the mathematicaldetails.
What does this have to do with storage?
When you pick a disk system, you are hoping you pick the door with the car. You want a disk system that meets your performance requirements for your particular workload and easy to deploy, configure and manage, with a low total cost of ownership for the three, four or five years you plan to use it.However, with over forty different storage vendors, there are some doors that might have goats. Some vendorshave only 90 day warranties for their software, and I don't know any customers that replace their disk systems that often.
(It was pointed out to me that it was unfair in my last week's post about[Xiotech'slow cost RAID brick], that I singled out EMC offering minuscule 90day warranties for the software needed to run their disk systems. I apologize. I have sincelearned that HDS and HP also shaft their clients with 90 day warranties. Apparently thereare a lot of vendors out there who lack confidence in the quality of their software!)
It would be nice if everyone published all of their performance benchmarks so that you canchoose the right door with the car behind it, but sadly in the storage industry, not everyoneparticipates with industry-standard benchmarks like the[Storage Performance Council].
In other cases, people make their choices based on past decisions. Perhaps someone beforethem chose one vendor over another, and it seems simple enough just to stay with the originalchoice. It is amazing how often people stay with their company's original choice, what we call in the industry the "incumbent vendor", without exploring alternatives.
So, if you bought an EMC, HDS or HP disk system in the last 90 days, it's not too late for you.Tell your local IBM rep that you are afraid you picked the door with the goat, and that you want to change your mind, and choose the other door and go with IBM instead.
You will double your chances of being happier with your new choice!
I am still wiping the coffee off my computer screen, inadvertently sprayed when I took a sip while reading HDS' uber-blogger Hu Yoshida's post on storage virtualization and vendor lock-in.
HDS is a major vendor for disk storage virtualization, and Hu Yoshida has been around for a while, so I felt it was fair to disagree with some of the generalizations he made to set the record straight. He's been more careful ever since.
However, his latest post [The Greening of IT: Oxymoron or Journey to a New Reality] mentions an expert panel at SNW that includedMark O’Gara Vice President of Infrastructure Management at Highmark. I was not at the SNW conference last week in Orlando, so I will just give the excerpt from Hu's account of what happened:
"Later I had the opportunity to have lunch with Mark O’Gara. Mark is a West Point graduate so he takes a very disciplined approach to addressing the greening of IT. He emphasized the need for measurements and setting targets. When he started out he did an analysis of power consumption based on vendor specifications and came up with a number of 513 KW for his data center infrastructure....
The physical measurements showed that the biggest consumers of power were in order: Business Intelligence Servers, SAN Storage, Robotic tape Library, and Virtual tape servers....
Another surprise may be that tape libraries are such large consumers of power. Since tape is not spinning most of the time they should consume much less power than spinning disk - right? Apparently not if they are sitting in a robotic tape library with a lot of mechanical moving parts and tape drives that have to accelerate and decelerate at tremendous speeds. A Virtual Tape Library with de-duplication factor of 25:1 and large capacity disks may draw significantly less power than a robotic tape library for a given amount of capacity.
Obviously, I know better than to sip coffee whenever reading Hu's blog. I am down here in South America this week, the coffee is very hot and very delicious, so I am glad I didn't waste any on my laptop screen this time, especially reading that last sentence!
In that report, a 5-year comparison found that a repository based on SATA disk was 23 times more expensive overall, and consumed 290 times more energy, than a tape library based on LTO-4 tape technology. The analysts even considered a disk-based Virtual Tape Library (VTL). Focusing just on backups, at a 20:1 deduplication ratio, the VTL solution was still 5 times per expensive than the tape library. If you use the 25:1 ratio that Hu Yoshida mentions in his post above, that would still be 4 times more than a tape library.
I am not disputing Mark O'Gara's disciplined approach. It is possible that Highmark is using a poorly written backup program, taking full backups every day, to an older non-IBM tape library, in a manner that causes no end of activity to the poor tape robotics inside. But rather than changing over to a VTL, perhaps Mark might be better off investigating the use of IBM Tivoli Storage Manager, using progressive backup techniques, appropriate policies, parameters and settings, to a more energy-efficient IBM tape library.In well tuned backup workloads, the robotics are not very busy. The robot mounts the tape, and then the backup runs for a long time filling up that tape, all the meanwhile the robot is idle waiting for another request.
(Update: My apologies to Mark and his colleagues at Highmark. The above paragraph implied that Mark was using badproducts or configured them incorrectly, and was inappropriate. Mark, my full apology [here])
If you do decide to go with a Virtual Tape Library, for reasons other than energy consumption, doesn't it make sense to buy it from a vendor that understands tape systems, rather than buying it from one that focuses on disk systems? Tape system vendors like IBM, HP or Sun understand tape workloads as well as related backup and archive software, and can provide better guidance and recommendations based on years of experience. Asking advice abouttape systems, including Virtual Tape Libraries, from a disk vendor is like asking for advice on different types of bread from your butcher, or advice about various cuts of meat at the bakery.
The butchers and bakers might give you answers, but it may not be the best advice.