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Three Talks

This paper explores the terminology and concepts surrounding scalability in computer systems, including the use of clones, partitions, and packs for achieving scalability and availability. It discusses the benefits and considerations of each approach and highlights real-world examples.

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Three Talks

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  1. Three Talks • Scalability Terminology • Gray (with help from Devlin, Laing, Spix) • What Windows is doing re this • Laing • The M$ PetaByte (as time allows) • Gray

  2. Geo Plex Farm Partition Clone Pack Shared Nothing Shared Disk Shared Nothing Active-Active Active-Passive Terminology for ScaleabilityBill Devlin, Jim Gray, Bill Laing, George Spix,,,,paper at: ftp://ftp.research.microsoft.com/pub/tr/tr-99-85.doc • Farms of servers: • Clones: identical • Scaleability + availability • Partitions: • Scaleability • Packs • Partition availability via fail-over • GeoPlex • for disaster tolerance.

  3. Unpredictable Growth • The TerraServer Story: • Expected 5 M hits per day • Got 50 M hits on day 1 • Peak at 20 M hpd on a “hot” day • Average 5 M hpd over last 2 years • Most of us cannot predict demand • Must be able to deal with NO demand • Must be able to deal with HUGE demand

  4. Web Services Requirements • Scalability: Need to be able to add capacity • New processing • New storage • New networking • Availability: Need continuous service • Online change of all components (hardware and software) • Multiple service sites • Multiple network providers • Agility: Need great tools • Manage the system • Change the application several times per year. • Add new services several times per year.

  5. Premise: Each Site is aFarm • Buy computing by the slice (brick): • Rack of servers + disks. • Functionally specialized servers • Grow by adding slices • Spread data and computation to new slices • Two styles: • Clones: anonymous servers • Parts+Packs: Partitions fail over within a pack • In both cases, GeoPlex remote farm for disaster recovery

  6. Scale UP Scaleable Systems • ScaleUP: grow by adding components to a single system. • ScaleOut: grow by adding more systems. Scale OUT

  7. Everyone does both. Choice’s Size of a brick Clones or partitions Size of a pack Who’s software? scaleup and scaleout both have a largesoftware component 1M$/slice IBM S390? Sun E 10,000? 100 K$/slice Wintel 8X 10 K$/slice Wintel 4x 1 K$/slice Wintel 1x ScaleUP and Scale OUT

  8. Clones: Availability+Scalability • Some applications are • Read-mostly • Low consistency requirements • Modest storage requirement (less than 1TB) • Examples: • HTML web servers (IP sprayer/sieve + replication) • LDAP servers (replication via gossip) • Replicate app at all nodes (clones) • Load Balance: • Spray& Sieve: requests across nodes. • Route: requests across nodes. • Grow: adding clones • Fault tolerance: stop sending to that clone.

  9. Shared Nothing Clones Shared Disk Clones Two Clone Geometries • Shared-Nothing:exact replicas • Shared-Disk (state stored in server) If clones have any state: make it disposable. Manage clones by reboot, failing that replace. One person can manage thousands of clones.

  10. Clone Requirements • Automatic replication (if they have any state) • Applications (and system software) • Data • Automatic request routing • Spray or sieve • Management: • Who is up? • Update management & propagation • Application monitoring. • Clones are very easy to manage: • Rule of thumb: 100’s of clones per admin.

  11. Partitions for Scalability • Clones are not appropriate for some apps. • State-full apps do not replicate well • high update rates do not replicate well • Examples • Email • Databases • Read/write file server… • Cache managers • chat • Partition state among servers • Partitioning: • must be transparent to client. • split & merge partitions online

  12. Packs for Availability • Each partition may fail (independent of others) • Partitions migrate to new node via fail-over • Fail-over in seconds • Pack: the nodes supporting a partition • VMS Cluster, Tandem, SP2 HACMP,.. • IBM Sysplex™ • WinNT MSCS (wolfpack) • Partitions typically grow in packs. • ActiveActive: all nodes provide service • ActivePassive: hot standby is idle • Cluster-In-A-Box now commodity

  13. Partitions Scalability Packed PartitionsScalability + Availability Partitions and Packs

  14. Parts+Packs Requirements • Automatic partitioning(in dbms, mail, files,…) • Location transparent • Partition split/merge • Grow without limits (100x10TB) • Application-centric request routing • Simple fail-over model • Partition migration is transparent • MSCS-like model for services • Management: • Automatic partition management (split/merge) • Who is up? • Application monitoring.

  15. GeoPlex: Farm Pairs • Two farms (or more) • State (your mailbox, bank account)stored at both farms • Changes from one sent to other • When one farm failsother provides service • Masks • Hardware/Software faults • Operations tasks(reorganize, upgrade move) • Environmental faults(power fail, earthquake, fire)

  16. DirectoryFail-Over Load Balancing • Routes request to right farm • Farm can be clone or partition • At farm, routes request to right service • At service routes request to • Any clone • Correct partition. • Routes around failures.

  17. 9 9 9 9 9 well-managed nodes Availability Masks some hardware failures well-managed packs & clones Masks hardware failures, Operations tasks (e.g. software upgrades) Masks some software failures well-managed GeoPlex Masks site failures (power, network, fire, move,…) Masks some operations failures

  18. Packed Partitions: Database Transparency SQL Partition 3 SQL Partition 2 SQL Partition1 SQL Database replication Web File StoreB Cloned Packed file servers The FARM: Clones and Packs of Partitions Cluster Scale Out Scenarios Web File StoreA SQL Temp State ClonedFront Ends(firewall, sprayer, web server) Web Clients Load Balance

  19. Some Examples: • TerraServer: • 6 IIS clone front-ends (wlbs) • 3-partition 4-pack backend: 3 active 1 passive • Partition by theme and geography (longitude) • 1/3 sysadmin • Hotmail: • 1000 IIS clone HTTP login • 3400 IIS clone HTTP front door • + 1000 clones for ad rotator, in/out bound… • 115 partition backend (partition by mailbox) • Cisco local director for load balancing • 50 sysadmin • Google: (inktomi is similar but smaller) • 700 clone spider • 300 clone indexer • 5-node geoplex (full replica) • 1,000 clones/farm do search • 100 clones/farm for http • 10 sysadmin See Challenges to Building Scalable Services: A Survey of Microsoft’s Internet Services,Steven Levi and Galen Hunthttp://big/megasurvey/megasurvey.doc.

  20. Acronyms • RACS: Reliable Arrays of Cloned Servers • RAPS: Reliable Arrays of partitioned and Packed Servers (the first p is silent ).

  21. Emissaries and Fiefdoms • Emissaries are stateless (nearly) Emissaries are easy to clone. • Fiefdoms are stateful Fiefdoms get partitioned.

  22. Geo Plex Farm Partition Clone Pack Shared Nothing Shared Disk Shared Nothing Active-Active Active-Passive Summary • Terminology for scaleability • Farms of servers: • Clones: identical • Scaleability + availability • Partitions: • Scaleability • Packs • Partition availability via fail-over • GeoPlex for disaster tolerance. Architectural Blueprint for Large eSites Bill Laing http://msdn.microsoft.com/msdn-online/start/features/DNAblueprint.asp Scalability Terminology: Farms, Clones, Partitions, and Packs: RACS and RAPS Bill Devlin, Jim Gray, Bill Laing, George Spix MS-TR-99-85 ftp://ftp.research.microsoft.com/pub/tr/tr-99-85.doc

  23. Three Talks • Scalability Terminology • Gray (with help from Devlin, Laing, Spix) • What Windows is doing re this • Laing • The M$ PetaByte (as time allows) • Gray

  24. What Windows is Doing • Continued architecture and analysis work • AppCenter, BizTalk, SQL, SQL Service Broker, ISA,… all key to Clones/Partitions • Exchange is an archetype • Front ends, directory, partitioned, packs, transparent mobility. • NLB (clones) and MSCS (Packs) • High Performance Technical Computing • Appliances and hardware trends • Management of these kind of systems • Still need good ideas on….

  25. Architecture and Design work • Produced an architectural Blueprint for large eSites published on MSDN • http://msdn.microsoft.com/msdn-online/start/features/DNAblueprint.asp • Creating and testing instances of the architecture • Team led by Per Vonge Neilsen • Actually building and testing examples of the architecture with partners. (sometimes known as MICE) • Built a scalability “Megalab” run by Robert Barnes • 1000 node cyber wall, 315 1U Compaq DL360s, 32 8ways, 7000 disks

  26. Clones and Packs aka Clustering • Integrated the NLB and MSCS teams • Both focused on scalability and availability • NLB for Clones • MSCS for Partitions/Packs • Vision is a single communications and group membership infrastructure and a set of management tools for Clones, Partitions, and Packs • Unify management for clones/partitions at BOTH: OS and app level (e.g. IIS, Biztalk, AppCenter, Yukon, Exchange…)

  27. Clustering in Whistler Server • Microsoft Cluster Server • Much improved setup and installation • 4 node support in Advanced server • Kerberos support for Virtual Servers • Password change without restarting cluster service • 8 node support in Datacenter • SAN enhancements (Device reset not bus reset for disk arbitration, Shared disk and boot disk on same bus) • Quorum of nodes supported (no shared disk needed) • Network Load Balancer • New NLB manager • Bi-Directional affinity for ISA as a Proxy/Firewall • Virtual cluster support (Different port rules for each IP addr) • Dual NIC support

  28. Geoclusters • AKA - Geographically dispersed (Packs) • Essentially the nodes and storage are replicated at 2 sites, disks are remotely mirrored • Being deployed today, helping vendors them get certified, we still need better tools • Working with • EMC, Compaq, NSISoftware, StorageApps • Log shipping (SQL) and extended VLANs (IIS) are also solutions

  29. Last year (CY2000) This work is a part of server scale-out efforts (BLaing) Web site and HPC Tech Preview CD late last year A W2000 “Beowulf” equivalent w/ 3rd-party tools Better than the competition 10-25% faster than Linux on SMPs (2, 4 & 8 ways) More reliable than SP2 (!) Better performance & integration w/ IBM periphs (!) But it lacks MPP debugger, tools, evangelism, reputation See ../windows2000/hpc Also \\jcbach\public\cornell* This year (CY2001) Partner w/ Cornell/MPI-Soft/+ Unix to W2000 projects Evangelism of commercial HPC (start w/ financial svcs) Showcase environment & apps (EBC support) First Itanium FP “play-offs” BIG tools integration / beta Dell & Compaq offer web HPC buy and support experience (buy capacity by-the-slice) Beowulf-on-W2000 book by Tom Sterling (author of Beowulf on Linux) Gain on Sun in the www.top500.org list Address the win-by-default assumption for Linux in HPC High Performance Computing No vendor has succeeded in bringing MPP to non-sci/eng venues & $$$… we will.

  30. Appliances and Hardware Trends • The appliances team under TomPh is focused on dramatically simplifying the user experience of installing the kind of devices • Working with OEMs to adopt WindowsXP • Ultradense servers are on the horizon • 100s of servers per rack • Manage the rack as one • Infiniband and 10 GbpsEthernet change things.

  31. Operations and Management • Great research work done in MSR on this topic • The Mega services paper by Levi and Hunt • The follow on BIG project developed the ideas of • Scale Invariant Service Descriptions with • automated monitoring and • deployment of servers. • Building on that work in Windows Server group • AppCenter doing similar things at app level

  32. Still Need Good Ideas on… • Automatic partitioning • Stateful load balancing • Unified management of clones/partitions at both app and OS level

  33. Three Talks • Scalability Terminology • Gray (with help from Devlin, Laing, Spix) • What Windows is doing re this • Laing • The M$ PetaByte (as time allows) • Gray

  34. Yotta Zetta Exa Peta Tera Giga Mega Kilo We're building Petabyte Stores Everything! Recorded • Soon everything can be recorded and indexed • Hotmail 100TB now • MSN 100TB now • List price is 800M$/PB(including FC switches & brains) • Must Geoplex it. • Can we get if for 1M$/PB? • Personal 1TB stores for 1k$ All BooksMultiMedia All LoC books (words) .Movie A Photo A Book 24 Yecto, 21 zepto, 18 atto, 15 femto, 12 pico, 9 nano, 6 micro, 3 milli

  35. Building a Petabyte Store • EMC ~ 500k$/TB = 500 M$/PB plus FC switches plus… 800 M$/PB • TPC-C SANs (Dell 18GB/…) 62 M$/PB • Dell local SCSI, 3ware 20 M$/PB • Do it yourself: 5 M$/PB • a billion here, a billion there, soon your talking about real money!

  36. 320 GB, 2k$ (now)6M$ / PB • 4x80 GB IDE(2 hot plugable) • (1,000$) • SCSI-IDE bridge • 200k$ • Box • 500 Mhz cpu • 256 MB SRAM • Fan, power, Enet • 500$ • Ethernet Switch: • 150$/port • Or 8 disks/box640 GB for ~3K$ ( or 300 GB RAID)

  37. Hot Swap Drives for Archive or Data Interchange • 25 MBps write(so can write N x 80 GB in 3 hours) • 80 GB/overnite = ~N x 2 MB/second @ 19.95$/nite Compare to 1$/GB via Internet

  38. 2 x 80GB disks 500 Mhz cpu (intel/ amd/ arm) 256MB ram 2 eNet RJ45 Fan(s) Current disk form factor 30 watt 600$ (?) per rack (48U - 3U/module - 16 units/U) 400 disks, 200 whistler nodes 32 TB 100 Billion Instructions Per Second 120 K$/rack, 4 M$/PB, per Petabyte (33 racks) 4 M$ 3 TeraOps (6,600 nodes) 13 k disk arms (1/2 TBps IO) A Storage Brick

  39. Each node has an OS Each node has local resources: A federation. Each node does not completely trust the others. Nodes use RPC to talk to each other COM+ SOAP, BizTalk Huge leverage in high-level interfaces. Same old distributed system story. What Software Do The Bricks Run? Applications Applications datagrams datagrams streams RPC ? ? RPC streams CLR CLR Infiniband /Gbps Ehternet

  40. 300 arms 50TB (160 GB/arm) 24 racks48 storage processors2x6+1 in rack Disks = 2.5 GBps IO Controllers = 1.2 GBps IO Ports 500 MBps IO My suggestion: move the processors into the storage racks. Storage Rack in 2 years?

  41. Auto Manage Storage • 1980 rule of thumb: • A DataAdmin per 10GB, SysAdmin per mips • 2000 rule of thumb • A DataAdmin per 5TB • SysAdmin per 100 clones (varies with app). • Problem: • 5TB is 60k$ today, 10k$ in a few years. • Admin cost >> storage cost??? • Challenge: • Automate ALL storage admin tasks

  42. It’s Hard to Archive a PetabyteIt takes a LONG time to restore it. • At 1GBps it takes 12 days! • Store it in two (or more) places online (on disk?).A geo-plex • Scrub it continuously (look for errors) • On failure, • use other copy until failure repaired, • refresh lost copy from safe copy. • Can organize the two copies differently (e.g.: one by time, one by space)

  43. Lets work together to make storage bricks Low cost High function NAS (network attached storage) not SAN (storage area network) Ship NT8/CLR/IIS/SQL/Exchange/… with every disk drive Call To Action

  44. Three Talks • Scalability Terminology • Gray (with help from Devlin, Laing, Spix) • What Windows is doing re this • Laing • The M$ PetaByte (as time allows) • Gray

  45. Cheap Storage • Disks are getting cheap: • 3 k$/TB disks (12 80 GB disks @ 250$ each)

  46. All Device Controllers will be Super-Computers Central Processor & Memory • TODAY • Disk controller is 10 mips risc engine with 2MB DRAM • NIC is similar power • SOON • Will become 100 mips systems with 100 MB DRAM. • They are nodes in a federation(can run Oracle on NT in disk controller). • Advantages • Uniform programming model • Great tools • Security • Economics (cyberbricks) • Move computation to data (minimize traffic) Tera Byte Backplane

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