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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
2
The Situation • GM’s IT transformation (aka Insourcing)
• Probably would have used consultants but couldn’t
• So we hired one!
5
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
6
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)
8
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
11
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
14
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 . . .
15
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
16
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
17
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
18
Reporting • Demantra is not a reporting tool
• We extract the forecast to a CSV
• Email to planners
• Future project will address reporting
21
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
23
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!
24
Status • Went live in Q4
• Monthly cadence with 2 scheduled forecast runs each month
• Going well
26
Status – Operational Issues • Have submitted 2 SRs
• DB objects become invalid
• DBA cleared SGA, recompiled stored procedures
• Engine hangs
• Reboot the Engine server
27
Future • Add causal factors
• Upgrade to Demantra 12.2.4
• WebLogic 12c
• 64-bit JDK
• Oracle Database 12c
29