Architecting Demantra:

Learning from GM's Experience

By: Jamie Anderson, Infrastructure Architect

Sales Planning & Intelligence, GBRD, GM IT

May 2015

Implementing Demantra without a sizable consulting

budget can be a daunting task, but GM did just that. The list

of decisions is overwhelming: Windows or Linux? Virtual or

physical? How many engines? WebLogic or WebSphere?

How much memory?

Many organizations have either bogged down or given up

before really getting started. Let's take a look at GM's

architecting and sizing process as a reference point from

which others can adopt, add, or subtract to make the

outcome more attainable.

Overview

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The Situation

The Situation • GM’s IT transformation (aka Insourcing)

• Probably would have used consultants but couldn’t

• So we hired one!

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GM’s Installation • Demantra 12.2.3

• Demand Management (DM)

• Advanced Forecasting and Demand Modelling (AFDM)

• Standalone – no EBS

• Engine runs Batch mode

• Linux

• Multi-tenant

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Sizing

Sizing • Sizing Demantra is very different from a transaction based application

• Use the Oracle VCP sizing tool

• Runs on Windows

• Answer a series of questions

• Submits answers via email with an XML file attachment

• See: Replacement of VCP / APS Sizer with Value Chain Planning

(VCP) Reference Sizing Tool (RAS) (Doc ID 1630684.1)

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Sizing • Sizing questionnaire:

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Sizing • And their response (sizing in bottom right):

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Sizing • Sizing is for executing 1 forecast with post-processing

• We were planning to run 4 forecasts over a weekend (48 hours)

• Engine Runtime – our answer was 8 hours

• 4 forecasts * 8 hours each + a few hours margin < 48 hours

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Architecture

Demantra Architecture

Source: Oracle 13

Not Your Typical 3-Tier Application • Unique characteristics of Demantra

• All data is stored at the lowest level of the hierarchy

• Analytical Engines can require large amounts of CPU and RAM

• Application Server is uncharacteristically slim, both in CPU and RAM

• It is not scalable because scale is not needed on this tier

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The Servers • Followed GM datacenter standard: Linux and Oracle

• Application Server: Linux VM

• Analytical Engines: Linux physical blades

• Administration: Windows Server

• Database: Oracle 11g

• The physical Linux blades were for performance and . . .

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OVM vs VMWare • In this release, VMWare is not officially supported. Please see My

Oracle Support Note 249212.1 for Oracle's policy on VMWare image

support. (installation guide)

• GM runs VMWare – datacenter said no OVM

• Big concern for future support

• Consensus from several sources was that it should not be a problem

• Performance benefits + support concerns = physical servers

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J2EE Application Server • Used on both the App Server and the Analytical Engine

• GM standard was WebLogic 11g at the time

• Any supported version – stay with your company’s standard

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Analytical Engine and JDK • Demantra requires 32-bit

• GM Datacenter only provides 64-bit WebLogic

• Workaround:

• Install 32-bit JDK

• Convert WebLogic to 32-bit

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Database • Oracle 11g per GM standard

• GM database team provided space on their RAC

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Reporting

Reporting • Demantra is not a reporting tool

• We extract the forecast to a CSV

• Email to planners

• Future project will address reporting

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Learnings

Learnings - Tablespaces • Installer asks for 7 tablespaces

• Ignores 5 of them

• Could impact performance

• Certainly wastes space

• Performance issues? Move the DB objects to different tablespaces

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Learnings - Data • How reliable and clean is your data source?

• This was our biggest issue by a factor of 10

• Double you data sourcing timeline and resources!

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Status

Status • Went live in Q4

• Monthly cadence with 2 scheduled forecast runs each month

• Going well

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Status – Operational Issues • Have submitted 2 SRs

• DB objects become invalid

• DBA cleared SGA, recompiled stored procedures

• Engine hangs

• Reboot the Engine server

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Future

Future • Add causal factors

• Upgrade to Demantra 12.2.4

• WebLogic 12c

• 64-bit JDK

• Oracle Database 12c

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GM is HIRING!

careers.gm.com

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Thank you!