Presentation on theme: "Microsoft Large Databases and Grid Computing"— Presentation transcript:
1Microsoft Large Databases and Grid Computing Jim GrayMicrosoft ResearchPresentation toKaiser Information Management Briefing21 May 2003
2About me in Microsoft research (located in San Francisco) A database researcherIBM, Tandem, DEC, MicrosoftWork on Scalable SystemsBuilding supercomputers from commodity components.Do academic/government things tooPITAC, GriPhyn TAB, NSF/CISE, Library of Congress, …For the last 4 years, been working with the astronomy community to build the World Wide Telescope.
3Agenda TerraServer SkyServer / WWT Grid Computing What it is What we learnedWhat we are doing now.SkyServer / WWTWhat we are doing nowGrid ComputingGeneral commentsBuild a web service
4TerraServer TerraService.net A photo of the United States1 meter resolution (photographic/topographic)USGS dataSome demographic data (BestPlaces.net)Home sales dataLinked to Encarta Encyclopedia15 TB raw, 6 TB cooked (grows 10GB/w)Point, Pan, zoom interfaceAmong top 1,000 websites40k visitors/day4M queries/day3 B page views (in 5 years)All in an SQL database
5TerraServer Statistics June ‘98Jan ‘99Jan ‘00May ‘00Sept ’01Dec ‘02Unique UsersPage ViewsImage TilesDb QueriesBytes XferedDailyAverage40,0111,266,8383,735,7894,484,08970 gbPeakDay277,29212,388,10410,475,674163 gb2,401,209JuneOct, 200263,656,9042,015,539,6055,943,641,0247,134,186,170108tb900 m Rows755m RowsSQL TB DbSQL TB DbSQL TB DbSQL Server 1.5 TB DbSQL Server .8 TB Db298 m RowsSQL TB Db231 m RowsSQL TB DbSQL TB Db217 m RowsSQL TB DbSQL TB Db173 m RowsSQL TB DbSQL TB Db1 Server / Win NT 4.0 EE2nd Server / Win 2k DataCenter4 Node / Win2k Datacenter Failover Cluster
68 Compaq DL360 “Photon” Web Servers 4 Compaq ProLiant 8500 Db Servers TerraServer Cluster8 Compaq DL360 “Photon” Web ServersOne SQL database per rackEach rack contains 4.5 TB1 rack not in picture18.0 TB total2200Fiber SANSwitchesEJOMeta DataStored on 101 GB“Fast, Small Disks” (18 x 18.2 GB)SQL\Inst1FGLKPQImagery DataStored on GB“Slow, Big Disks”(15 x 73.8 GB)This is a picture of the original TerraServer database server located at Microsoft’s Internet Data Center. This system was the primary database server from when we launched the TerraServer web site in June 1998 until the system was retired in October I claim that is the world’s largest PC, checking in at 24.5 feet and approximately 7 tons. I have not been challenged on this pointThe white cabinet on the right is the DEC AlphaServer It has 8 440mhz processors and 10GB of RAM. We are running NT Server V4.0 Enterprise Edition which only uses 2 GB of RAM. But we were well prepared to migrate to Windows 2000 Data Center edition. There are seven slate blue cabinets to the left of the processor. These house the Compaq StorageWorks disk arrays -- containing the UltraSCSI disk drives and HSZ70 Raid controllers. There are a total of GB drives per cabinet. Each drive is connected to two HSZ70 controllers that operate in a hot-standby, failsafe mode. The HSZ70 binds 11 drives into a single RAID-5 control set. 2 Drives per cabinet are used as “hot spares” and are transparently swapped in in case there is a disk failure. Each HSZ70 pair is connected to a separate KPSB controller on in the DEC Alpha 8400 CPU cabinet. The last white box on the far left is our StorageTek TimberWolf 9710 tape robot. It contains 10 Quantum DLT7000 tape drives. A pair of DLT7000 drives are connected on a Fast Wide Differential SCSI connection to the DEC AlphaServer The StorageTek tape robot takes commands from Legato Networker to backup or restore database files to/from the tape drives. Legato Networker is able to move data to/from all 10 tape drives in parallel. Using file backup, this configuration can backup the entire 1.0 TB SQL Server database files in 7 hours and 15 minutes.Also note, this picture does not include the web servers. We started with 4 Compaq ProLiant x200 mhz systems. They were approximately 18” high, rack mounted. We had our systems “scattered” around the data center, thus we don’t have a picture of them together. They would consume two racks with monitors.Oh and the attractive woman standing in front our the hardware is not a model but LeeAnn Stivers, our Compaq partner on the TerraServer project.My point in showing you the original configuration is to show the incredible rate of change in the hardware business. This system was “state of the art” when we first received it in early Back then, a single system with over 2.4 TB of disk space was hard to imagine in the PC world. The next slide is the current TerraServer “cluster” of processors. <Click or press ENTER NOW>Here is the current TerraServer. Instead of 10 racks of equipment, we only have 5 racks! On the right are two racks, with one half empty, containing the processors. The second rack contains the 3 active database servers, 1 spare database server, and the Storage Area [fiber] Network hubs. The SAN connects to our 13.7 TB of Compaq StorageWorks RAID 10 disk arrays. This configuration is highly available. Instead of using RAID-5 technology as we have in the past, we have opted for mirroring physical volumes. Instead of dual- mirror, we have tripled mirrored each disk. That is one “logical” disk is comprised of three physical disks.We were one of the first to receive 73 GB (72.8 GB actually) hard drives in August These disks spin at 10k RPM and store all our imagery. We also have smaller, 18GB 15k RPM “fast drives”. These drives store all the meta-data about TerraServer imagery, the search system, and the Gazetteer. Note, most “difficult/complicated” queries execute against these drives.On the right rack at the top are eight web servers. Each server is 1 “rack unit”, i.e. “1U” tall, and contains mhz processors, 734kb of RAM, 2 18 GB hard drives, and 2 100mb/1gb network cards. Wow.Since we’ve taken this picture, an additional rack containing 4.5 TB of 73 GB drives has been added on the left. Also, we are replacing our StorageTek 9710 robot, (who’s lower panel can be seen through the bottom of the right most rack in the back), with a Scalar 1000 ADIC robot. While we very happy with StorageTek, the DLT drives and media have been less than satisfactory for us. This year, we have worked with ADIC on testing LTO technology. We have found it superior in raw performance, space usage, and reliability when compared to DLT media. The ADIC Scalar 1000 will be put into the production environment during the summer of 2001.SQL\Inst2IHMNRSSQL\Inst3Added GBDisks in Feb 2001to create 18 TB SANSpare4 Compaq ProLiant 8500 Db Servers
7Cluster Configuration InternetCisco 12000Internet RouterTerraServer SANGigibitEthernet1CompaqStorageWorksDatabase100-MbpsEthernetCompaq DL360 (10)ClusterMA8000/HSG80Controllers (3)2Summit 7iSwitch (2)Compaq DL360 (6)(Windows 2000 Web Servers)TerraServer.microsoft.comOne of the main goals of TerraServer is to demonstrate how to build a highly available and scalable configuration using commercially available, “off the shelf”, commodity hardware running on Microsoft software. In TerraServer’s particular case, we are showing high-end, or “enterprise” customers how we recommend they configure a complete, highly scalable, highly reliable system using off-the-shelf, commodity hardware and software. This particular diagram shows off the key elements of our high availability story.TerraServer is located in Microsoft’s Tukwila Data Center. This is a location near the SEATAC airport south of Seattle. Microsoft’s Internal Technology Group (ITG) provides a high speed link to the internet. We host our own network environment running on Extreme Data Networks gigabit over copper technology. We have on fiber to the internet. This is the “green” line that separates out web servers, “TkTerra#” from the internet. The Extreme network hardware implements a “Virtual IP”, a.k.a. “a VIP”, address, for and The Extreme network equipment routes requests to TkTerra1 thru TkTerra TkTerra7, TkTerra8, TkTerra9, and TkTerra10 service a second VIP for More on that web site later.A second, “private network”, is created by our Extreme networking gear to connect the web servers with the four-node Windows 2000 Data Center cluster. This network is shown in pink. It is a 1 gigabit over copper network that only the web servers and database servers are connected too.The orange lines represent a third network. It is the connection to the Microsoft “corporate LAN” in Redmond Washington. This enables us to load data from our systems located on the Redmond campus “over the wire” to Tukwila. It also lets us remotely log into the database servers with Terminal Server and manage the systems. For security reasons, we cannot directly access the web servers from the corporate Lan. We can reach these systems by first logging into a TerraServer database server.The key attribute of any highly available configuration is no single point of failure. I’ve talked at length about the network so far. Having 10 web servers with 50% wired to one network switch and the other 50% wired to the second network switch ensures that no single web server’s failure or network switch failure can take TerraServer off-line. Yes, we have roughly double the web server capacity that we really use on a normal day. Actually, we have 3-to-1 the “normal” capacity, such that if 50% of our web servers are un-available, we still have excess capacity. On a peak day, which typically are 3-to-1 a normal day, we would run in a degraded mode if we lost all the web servers on a single network switch.The red boxes in the center represent the four Compaq 8500 processors that comprise our database cluster of processors. They too are split between Extreme network switches for network performance balancing purposes and for availability. To the left, the lines depict the redundant paths to the Compaq StorageWorks disk arrays of triple mirrored disks. We use Brocade “Silkworm” 16 port fiber hubs, sold and distributed by Compaq to implement our SAN network. The Silkworm hubs are configured such that there are 3 separate SAN “fabrics”. The 1st fabric shown at the top, implements two redundant paths between each Compaq processor and the 1st fabric, and two separate paths between each of the Compaq StorageWorks disk controllers, which happen to be MA8000 units with HSG80 dual redundant controllers.The 2nd fabric, shown in the middle, also connects the Compaq 8500 processors in a dual redundant manner to the all the Compaq HSG80 storage controllers. There is a separate HBA controller on the Compaq 8500 processors for each fabric. When we added the additional rack of disks, we also added a third Brocade Silkworm switch to fabric #1 and #2. This gave us the required ports we needed to manage all 18 TB, in a fully redundant manner on the two SAN switch.When we added the third Brocade Silkworm to each fabric, we also installed a 3rd fabric managed by another Brocade Silkworm switch, and includes a 3rd HBA installed in each Compaq The 3rd fabric exists to connect our ADIC Scalar 1000 to the Compaq SAN.Thus, we never lose connectivity between a processor and disks due to a hardware failure.CompaqSAN switchby BrocadeCommunicationsInternetExtremeNetworksSummit 48SwitchADICLTOTapeLibrary3CompaqProLiant 8500(4)MicrosoftCorporate LAN
8TerraServer Becomes a Web Service TerraServer. net -> TerraService TerraServer Becomes a Web Service TerraServer.net -> TerraService.NetWeb server is for people.Web Service is for programsThe end of screen scrapingNo faking a URL: pass real parameters.No parsing the answer: data formatted into your address space.Hundreds of users but a specific example:US Department of Agriculture
9And now.. 4 slides from the “customer” who built a portal using TerraService
10Data Gateway Functional Overview ITC - Fort Collins, ColoradoNCGC - Fort Worth, TexasCustomer Orders DataTerraServiceBilling ServicesSoil Data ViewerNavigation ServiceRimage CD ServiceXMLXMLXMLFTP ServicesASPCatalog ServiceShip Service<<Requests Products>>Package ServiceSend order infoOrder Placervalidate (dtd)Insert into SQL/ GUID to clientreturn est timeraise OrderMgr.eventProduct Catalog UpdatesGeospatial DataOrder DatabaseData ServicesCalled by anyoneLoggerXML Request for datarasies to stats svc'Selects fromItem BrokerListen for OrderPlacer RaisedEventSelect sequenced ItemOutput XMLAcknowledges item ready for deliveryrasie event : stats.delivery start
11Custom End Product Soil Interpretation Map Web Soil Data Viewer XML Soil Report
12Business Rules National Soils Data Geospatial Data Terraserver Web Server - COM+ ApplicationsArcIMS ConnectorWebSDVIMSNavigatorImage RetrieverConnects to ArcIMS; communication is done through ArcIMS XML (AXL)Retrieves and processes Soils Data from the NASIS relational DatabaseGenerates maps (JPGs) using ArcIMSRetrieves imagery from the Microsoft TerraServerDatabase Server - ESRI Spatial Data ServerESRISpatial Data EngineDatabase Server - Microsoft SQL ServerBusinessRulesNational Soils DataGeospatial DataMicrosoft TerraserverTerraserver
13Brief tour of TerraService Show map serviceShow some methodsSeeTerraService.NET: An Introduction to Web Services Tom Barclay; Jim Gray; Eric Strand; Steve Ekblad; Jeffrey Richter, MSR TR , pp 13, June 2002
14What We LearnedYou can build and manage a very popular website with relatively little effort (if you do it right and have Tom Barclay)Loading 20 TB takes a lot of energyAnd you get to do it many times -- automateTape and tape software are problematicTriplex and snap-shot disks works (we have never had to use it, but..)The internet gives you 2-9’s Servers can run at 4 9’s easily, 5 9’s with effort.
15What we are doing now. Building with 3K$ 2TB bricks 4 bricks = 1 backendTriplexing systemsDuplexing sites.4*3*2 = 24k$ for GeoplexVery simple operations modelSee:“TeraScale SneakerNet: Using Inexpensive Disks for Backup, Archiving, and Data Exchange,” Jim Gray; Wyman Chong; Tom Barclay; Alex Szalay; Jan Vandenberg, pp. 1-8, May 2002
16Agenda TerraServer SkyServer / WWT Grid Computing What it is What we learnedWhat we are doing now.SkyServer / WWTWhat we are doing nowGrid ComputingGeneral commentsBuild a web service
17SkyServer SkyServer.SDSS.org Like the TerraServer, but looking the other way: a picture of ¼ of the universePixels + Data MiningAstronomers get about 400 attributes for each “object”Get Spectrograms for 1% of the objects
18Why Astronomy Data? It has no commercial value IRAS 25mIt has no commercial valueNo privacy concernsCan freely share results with othersGreat for experimenting with algorithmsIt is real and well documentedHigh-dimensional data (with confidence intervals)Spatial dataTemporal dataMany different instruments from many different places and many different timesFederation is a goalThe questions are interestingHow did the universe form?There is a lot of it (petabytes)2MASS 2mDSS OpticalIRAS 100mWENSS 92cmNVSS 20cmGB 6cmROSAT ~keV
19Demo of SkyServer Shows standard web server Pixel/image data Point and clickExplore one objectExplore sets of objects (data mining)
20Virtual Observatory http://www.astro.caltech.edu/nvoconf/ http://www.voforum.org/ Premise: Most data is (or could be online)So, the Internet is the world’s best telescope:It has data on every part of the skyIn every measured spectral band: optical, x-ray, radio..As deep as the best instruments (2 years ago).It is up when you are up. The “seeing” is always great (no working at night, no clouds no moons no..).It’s a smart telescope: links objects and data to literature on them.
21Time and Spectral Dimensions The Multiwavelength Crab Nebulae Crab star1053 ADX-ray,optical,infrared, andradioviews of the nearby Crab Nebula, which is now in a state of chaotic expansion after a supernova explosion first sighted in 1054 A.D. by Chinese Astronomers.Slide courtesy of Robert CalTech.
22Data Federations of Web Services Massive datasets live near their owners:Near the instrument’s software pipelineNear the applicationsNear data knowledge and curationSuper Computer centers become Super Data CentersEach Archive publishes a web serviceSchema: documents the dataMethods on objects (queries)Scientists get “personalized” extractsUniform access to multiple ArchivesA common global schemaFederation
23Grid and Web Services Synergy I believe the Grid will be many web services share data (computrons are free)IETF standards ProvideNamingAuthorization / Security / PrivacyDistributed ObjectsDiscovery, Definition, Invocation, Object ModelHigher level services: workflow, transactions, DB,..Synergy: commercial Internet & Grid tools
24Web Services: The Key? Internet-scale distributed computing Web SERVER:Given a url + parametersReturns a web page (often dynamic)Web SERVICE:Given a XML document (soap msg)Returns an XML documentTools make this look like an RPC.F(x,y,z) returns (u, v, w)Distributed objects for the web.+ naming, discovery, security,..Internet-scale distributed computingYourprogramWebServerhttpWeb pageYourprogramWebServicesoapDataIn your address spaceobject in xml
25SkyQuery: a prototype Defining Astronomy Objects and Methods. Federated 3 Web Services (fermilab/sdss, jhu/first, Cal Tech/dposs) multi-survey cross-match Distributed query optimization (T. Malik, T. Budavari, Alex JHU)My first web service (cutout + annotated SDSS images) onlineWWT is a great Web Services (.Net) applicationFederating heterogeneous data sources.Cooperating organizationsAn Information At Your Fingertips challenge.
26Demo of Image Cutout Service Shows image cutoutShow project and debugging projectShow hello WorldShow “theAnswer” method
27SkyQuery (http://skyquery.net/) Distributed Query tool using a set of servicesFeasibility study, built in 6 weeks from scratchTanu Malik (JHU CS grad student)Tamas Budavari (JHU astro postdoc)Implemented in C# and .NETAllows queries like:SELECT o.objId, o.r, o.type, t.objIdFROM SDSS:PhotoPrimary o,TWOMASS:PhotoPrimary tWHERE XMATCH(o,t)<3.5AND AREA(181.3,-0.76,6.5)AND o.type=3 and (o.I - t.m_j)>2
28SkyNode Basic Web Services Metadata information about resourcesWavebandSky coverageTranslation of names to universal dictionary (UCD)Simple search patterns on the resourcesCone SearchImage mosaicUnit conversionsSimple filtering, counting, histogrammingOn-the-fly recalibrations
29Portals: Higher Level Services Built on Atomic ServicesPerform more complex tasksExamplesAutomated resource discoveryCross-identificationsPhotometric redshiftsOutlier detectionsVisualization facilitiesGoal:Build custom portals in days from existing building blocks (like today in IRAF or IDL)
30Architecture Image cutout SkyNode First Web Page SkyQuery SkyNode 2MassSkyNode SDSS
31Summary So Far Some real web services deployed today Easy to build & deployServices publish data, Portals unify itTools really work!I’m using C# and foundation classes of VisualStudio, a great! ToolA nice book explaining the ideas: (.Net Framework Essentials, Thai, Lam isbn )
32Possible Relevance to You This web service stuff is REALIf you have a class, It is a way to publish data: Internet IntranetIt is a way to find data data comes with schema no more screen scraping/parsingBusiness model unclearYour ideas go here.YourprogramDataIn your address spaceWebServicesoapobject in xml
33What We Learned Web services really are a breakthrough. Data mining worked beautifully. See Data Mining the SDSS SkyServer Database,” J. Gray, D. Slutz, A. Szalay, A. Thakar, P. Kuntz, C. Stoughton, MSR TR , pp1-40, 2002.You can operate a system in Chicago from San Francisco – Terminal Server is wonderful.The Internet gives you 2 9’s of availabilityTeraScale SneakerNet works well
34What we are doing now. Loading more data (next data release) Preparing for the next generationBuilding the WWTWeb Services for the Virtual Observatory, Alexander S. Szalay, Tamás Budavária, Tanu Malika, Jim Gray, and Ani Thakar, SPIE Astronomy Telescopes and Instruments, August 2002, Waikoloa, Hawaii,Petabyte Scale Data Mining: Dream or Reality?, Alexander S. Szalay; Jim Gray; Jan vandenBerg, SIPE Astronomy Telescopes and Instruments, August 2002, Waikoloa, Hawaii,Online Scientific Data Curation, Publication, and Archiving Jim Gray; Alexander S. Szalay; Ani R. Thakar; Christopher Stoughton; Jan vandenBerg, SPIE Astronomy Telescopes and Instruments, August 2002, Waikoloa, Hawaii,
35Agenda TerraServer SkyServer / WWT Grid Computing What it is What we learnedWhat we are doing now.SkyServer / WWTWhat we are doing nowGrid ComputingGeneral commentsBuild a web service
36The Grid Computation Grid: harvest Internet cpus. Data Grid: Share filesApplication Grid: Web servicesAccess Grid: teleconferencing
37The Microsoft View Web Services will subsume the Grid The Grid will be data and services not renting cyclesOGSA: evolution of Globus Toolkit to Web services concepts and technologies…Lots of encouragement from Microsoft, IBM, Oracle, SunGGF as forum for discussion
38Engagement with Grid Community Goal: GXA as infrastructure for GridsWorking with Globus & GGFFunding work at Argonne National Lab (Globus)Globus Toolkit 3, and CondorG on Windows(we sponsored this)OGSA for .NET (prototyping)Also OGSI.NET at U. VA is very interestingGGFActive membershpHPC .net kit – seePart of .net server scale out developmentIncludes MPI-CH 1.2.4, distributed job scheduler,…Thomas Sterling, Beowulf on Windows, MIT Press 2001
39What’s Microsoft Doing Mostly .NET, W3C standards, web services, …I think SkyQuery is the best web service (grid app) in GriPhyN today.My stuff is grid computingBut…Globus (GT3), OGSA, and CondorG ported to Windows (we sponsored it)We have a HPC toolkit: MPI-CH 1.2.4See for many useful links
40I Can Talk About Computing on Demand But… Best to read Distributed Computing Economics, Jim Gray, MSR-TR , March 2003The slides that follow are based on that paper.
41Distributed Computing Economics Why is a great ideaWhy is Napster a great deal?Why is the Computational Grid uneconomicWhen does computing on demand work?What is the “right” level of abstractionIs the Access Grid the real killer app?
42Computing is Free Computers cost 1k$ (if you shop right) So 1 cpu day == 1$If you pay the phone bill (and I do) Internet bandwidth costs 50 … 500$/mbps/m (not including routers and management).So 1GB costs 1$ to send and 1$ to receive
43Why is Seti@Home a Good Deal? Send 300 KB for costs 3e-4$User computes for ½ day: benefit .5e-1$ROI: 1500:1
44Why is Napster a Good Deal? Send 5 MB costs 5e-3$½ a penny per songBoth sender and receiver can afford it.Same logic powers web sites (Yahoo!...):1e-3$/page view advertising revenue1e-5$/page view cost of serving web page100:1 ROI
45The Cost of Computing: Computers are NOT free! Capital Cost of a TpcC system is mostly storage and storage software (database)IBM 32 cpu, 512 GB ram 2,500 disks, 43 TB (680, $/tpmc available 11/08/03)A 7.5M$ super-computerTotal Data Center Cost: 40% capital &facilities 60% staff (includes app development)
46Computing Equivalents 1 $ buys 1 day of cpu time4 GB ram for a day1 GB of network bandwidth1 GB of disk storage10 M database accesses10 TB of disk access (sequential)10 TB of LAN bandwidth (bulk)
47Some consequencesBeowulf networking is 10,000x cheaper than WAN networking factors of 105 matter.The cheapest and fastest way to move a Terabyte cross country is sneakernet. 24 hours = 4 MB/s 50$ shipping vs 1,000$ wan cost.Sending 10PB CERN data via network is silly: buy disk bricks in Geneva, fill them, ship them – one way.TeraScale SneakerNet: Using Inexpensive Disks for Backup, Archiving, and Data ExchangeJim Gray; Wyman Chong; Tom Barclay; Alex Szalay; Jan vandenBergMicrosoft Technical Report may 2002, MSR-TR
48How Do You Move A Terabyte? Time/TB$/TB Sent$/MbpsRent $/monthSpeed MbpsContext6 years3,0861,000400.04Home phone5 months360117700.6Home DSL2 months2,4698001,2001.5T12 days2,01065128,00043T314 hours97631649,000155OC314 minutes6172001,920,0009600OC 1921 day100100 Mpbs2.2 hours1000Gbps
49Computational Grid Economics To the extent that computational grid is like or ZetaNet or or… it is a great thingThe extent that the computational grid is MPI or data analysis, it fails on economic grounds: move the programs to the data, not the data to the programs.The Internet is NOT the cpu backplane.The USG should not hide this economic fact from the academic/scientific research community.
50Computing on DemandWas called outsourcing / service bureaus in my youth. CSC and IBM did it.Payroll is standard outsource.Now we have Hotmail, Salesforce.com, Oracle.com,….Works for standard apps.Airlines outsource reservations. Banks outsource ATMs.But Amazon, Amex, Wal-Mart, ... Can’t outsource their core competence.So, COD works for commoditized services.It is not a new way of doing things: think payroll.
51What’s the right abstraction level for Internet Scale Distributed Computing? Disk block? No too low.File? No too low.Database? No too low.Application? Yes, of course.Blast searchGoogle searchSend/GetPortals that federate astronomy archives (http://skyQuery.Net/)Web Services (.NET, EJB, OGSA) give this abstraction level.
52Access Grid Q: What comes after the telephone? A: eMail? A: Instant messaging?Both seem retro technology: text & emotons.Access Grid could revolutionize human communication.But, it needs a new idea.
53Distributed Computing Economics Why is a great idea?Why is Napster a great deal?Why is the Computational Grid uneconomicWhen does computing on demand work?What is the “right” level of abstraction?Is the Access Grid the real killer app?Based on: Distributed Computing Economics, Jim Gray, Microsoft Tech report, March 2003, MSR-TR
54Agenda TerraServer SkyServer / WWT Grid Computing What it is What we learnedWhat we are doing now.SkyServer / WWTWhat we are doing nowGrid ComputingGeneral commentsBuild a web service