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Understand the differences between scale out and scale up approaches, their advantages and challenges, and how to make the right choice for your high-performance system.
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Scaleout vs. ScaleupRobert BarnesMicrosoft HPTS'99 Scale Out vs Scale Up
CPU 50 GB Disc 5 GB RAM Why 1BTPD? • We had two main obstacles in bringing TP to Microsoft: • Lack of products and infrastructure • Industry mindshare and/or credibility • After starting to address the first obstacle, we decided to build something to demonstrate Microsoft has a credible platform for large-scale applications HPTS'99 Scale Out vs Scale Up
CPU 50 GB Disc 5 GB RAM Why 1BTPD? • We liked Jim Gray’s “cyber-brick” machine and wanted to build one - only the technology wasn’t there yet • The closest thing to it was a collection of laptops - so we wanted to tie together 1000 laptops. We decided DebitCredit would be a good workload to run, and 10KTPS* DebitCredit was born *10 K Transactions per Second HPTS'99 Scale Out vs Scale Up
Why DebitCredit? • We needed a DB-only benchmark • Do not want to configure one million terminals • A simple transaction profile to stress DTC • Many little transactions • Need distributed transactions to stress DTC • TPC-B is dead (can not report numbers) • TPC-C is not server-only (need 1 million terminals) and requires distributed data transparency • So, we returned to the Datamation Benchmark (1985) HPTS'99 Scale Out vs Scale Up
10KTPS 1BTPD • Work began on the benchmark in mid 1995 • A vendor released a 30K TPM-C number • Even though 10KTPS is 600Ktpm and DebitCredit is very different from TPC-C transactions, we needed a different metric • 11574.07 tps = 694444.2 tpm = 41666652 tph = 1 Billion Transactions Per Day* *thanks, Jim HPTS'99 Scale Out vs Scale Up
Scaling HPTS'99 Scale Out vs Scale Up
Scaleable SystemsSMP and Loosely Coupled Systems Scaleup with SMP8P is new standard (SHV) Scaleout with Loosely Coupled Systems (LCS) using inexpensive parts SMP SuperServer Departmental Server LCS of PCs or SHVs Personal System HPTS'99 Scale Out vs Scale Up
SMP Advantages • Single system image • no change to operations (relative to uniprocessor) • no change to applications • Simple system resources • shared memory • shared disk • shared net • Load balancing in OS kernel • 8x SMP soon commodity SHV SMP Super Server Departmental Server Personal System HPTS'99 Scale Out vs Scale Up
SMP Problems • Problems: • More then 8 processors not a commodity today • More than 16 processors may require partitioning, scale out needed anyway • scale-down problem (starter systems expensive or fork lift upgrade) • Potential single point of failure • Eventually stops scaling SMP Super Server Departmental Server Personal System HPTS'99 Scale Out vs Scale Up
SMP Performance Diminishing returns Linear extrapolation for 16 HPTS'99 Scale Out vs Scale Up
LCS Advantages • Advantages: • No hardware limit to scale, given a scaleable interconnect and an application that partitions • Uses high volume,commodity components • No single point of failure • Upgrade by incremental growth Load Balancing Common Function HPTS'99 Scale Out vs Scale Up
LCS Problems • Operations complexity • When not designed for LCS, costs can be very expensive • Change in system architecture; e.g. Exchange, SQL Server (relative to uniprocessor) • Need additional system services • Load Balancing • LCS Membership • Configuration replication • Failure Retry (within LCS) • Parallelism needed for data and applications • explicit parallelism exposes partitions to the application • implicit parallelism requires transparency Load Balancing Common Function HPTS'99 Scale Out vs Scale Up
givememoney.com • The givememoney.com business is brokering – their goal is to not directly handle any products • Site is currently <10 stores, plan to be hundreds in a few years • Books, music, video,computers,software,games,surplus • It takes over 90 days to add a new store • Over 90 servers make up current site • Today, checkouts/day 10K • Business plan calls for 500K by 2002 HPTS'99 Scale Out vs Scale Up
givememoney.com FE 5 2 5 2 2 Cache Server ASP SSL ASP SSL FARM B FARM A Basket/Ad/Surplus ASP File Server SQL Product Server ASP File Server SQL Product Server Receipt/Fulfillment Games/Music Videos Games/Music Videos Monitor and cache Comp/Soft Books Comp/Soft Books Music Music Search Servers Search Servers HPTS'99 Scale Out vs Scale Up
givememoney.com • “We don’t have a scaling problem – if we need more capacity, we just add a server. We have a management problem…” HPTS'99 Scale Out vs Scale Up
Scale Out Business Need • givememoney.com is at 10K orders/day, business plan is to grow to 500K by 2002 • Moore’s law says scale improves by 4X in 3 years, givememoney.com wants 50X , over 10X Moore’s law. • Even if you believe Moore’s law solves the growth problem, it requires many forklift upgrades • We still have to scale up – as it minimizes the number of servers needed… HPTS'99 Scale Out vs Scale Up
Consolidation • Not consolidation vs. scale out • Consolidation motivations • Business • Site (Space) • Operations • Storage • Reasons for never wanting to have 1 huge system • Single point of failure • Dis-economies of scale up • Mixed workload has operations challenges similar to scale out • Difficulty of dealing with growth HPTS'99 Scale Out vs Scale Up
Scaleout is a software challenge • Scaleup is hardware architecture & OEM driven • Optimized by Software • e.g. minimize locking, parallel threads, reduce contention on critical sections, etc. • Ultimately, scale up begins to look like scale out (partitioning) • Scaleout is software architecture driven • Optimized by hardware • e.g. SAN (system area nets), low latency/high bandwidth interconnects • Primarily an application design and operational management problem • Possible today, but mostly left to application design/development and ad hoc management tools HPTS'99 Scale Out vs Scale Up
Summary • Scaleup begins to look like scaleout as you add processors • Scaleout with commodity hardware is economically compelling • Every large successful web site uses scaleout – it is practical, but hard • Operations complexity is the key barrier to scaleout HPTS'99 Scale Out vs Scale Up
CyberWall HPTS'99 Scale Out vs Scale Up