The document discusses the 6 Rs migration strategy for identifying migration options to AWS: Retain, Retire, Rehost, Replatform, Refactor, and Rearchitect (Replace). It provides descriptions and considerations for each option. It also discusses Scholastic's use of various migration strategies like Retain, Rehost/Replatform, Rearchitect, and Refactor for different applications. The document emphasizes using an assessment-based approach and mapping business drivers to the appropriate migration strategy.

1. © 2016, Amazon Web Services, Inc. or its Affiliates. All rights reserved.© 2016, Amazon Web Services, Inc. or its Affiliates. All rights reserved.
Nirav Kothari, Principal Consultant
AWS Professional Services
Jeffrey Gelb, Head of Foundational Engineering
Scholastic Inc.
November 30, 2016
Identifying Your Migration
Options: The 6 Rs

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Agenda
In this session, we will cover:
• The 6 Rs of migration
• Assessment-based approach
• Considerations when selecting the various Rs
• Discuss each R of migration strategy
• How Scholastic leveraged the 6 Rs

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6 Rs migration strategy
Retain (Revisit) Replatform
Retire Refactor
Rehost Rearchitect (Replace)
• Customers will keep host/application in their
source environment
• Minimal analysis/validation of scope and
application affinity
• Dependency on integrating service
management
• Application and host decommission on source
• No migration to target
• Application owner approvals needed
• Like for like application migration to target
cloud
• Minimal effort to make the application work on
the target cloud infrastructure (minimal
application layout change)
• Storage migration will be needed (without
conversion)
• Up-version of the OS and/or database onto the
target cloud
• Some level of application changes
• Application reinstallation on the target
• Database to Amazon RDS
• OS and/or database porting
• Middleware and application change to cloud
service offering
• Data conversion; Database transition to MySQL,
Amazon Aurora, or other
• Application architecture changes may also require
Up-version or Porting
• Use SaaS-based offerings, application architecture
changes may require porting
• Middleware, data modernization; application
consolidation/stacking
1
2
3
4
5
6

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Assessment-based approach
• Financial assessment
• Security assessment
• Compliance and regulatory
assessment
• Business assessment
• Technical assessment
• Contractual assessment

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Application considerations
• What is the application roadmap?
• What are the costs associated with this application?
• What improvement options are available to enhance service?
• Are there any risks of not making changes to this application?
• Where does this application align with the technology goals of
the organization?

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Mapping drivers to migration strategy
BusinessAgility/Value
Migration EffortLow High
High
Retire
Retain (Revisit)
Rehost
Replatform
Refactor
Rearchitect (Replace)

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Retain
• Unsupported OS and applications
• Legacy applications that do not have
a business justification for migrating
to the cloud
Physical Machine/Virtual Machine Image
App Binary
Operating System Files
Disk Volumes
Disk Drives
Memory
NIC
User Data
Retain Retire Rehost Replatform Refactor
Rearchitect
(Replace)

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Retire
• Duplicate resources due to M&A
• Resources part of an existing
decommissioning program scope
• Clustered hosts for DR purposes
• Alternative HA hosts
Physical Machine/Virtual Machine Image
App Binary
Operating System Files
Disk Volumes
Disk Drives
Memory
NIC
User Data
Retain Retire Rehost Replatform Refactor
Rearchitect
(Replace)

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Rehost
Physical Machine/Virtual Machine Image
App Binary
Operating System Files
Disk Volumes
Disk Drives
Memory
NIC
User Data
Amazon EC2
New Disk Volumes
Operating System Files
App Binary User Data
Rehost
• Servers running packaged
software
• Applications without an
active roadmap
• Ad hoc, dev, and test
environments
Retain Retire Rehost Replatform Refactor
Rearchitect
(Replace)

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Rehost
ConsPros
 Speed of migration
 Reduced risk of migration
 AWS + partner ecosystem-offered tools to
natively support this migration strategy
 Migration could be application, hypervisor, and
physical hardware agnostic
 Could be automated/tool assisted
 Supports migration of system with
configuration
 Rehost is not OS agnostic; you will retain the
same OS and settings in the target
environment
 You may not use AWS services that give you
operational scale like Amazon RDS, Amazon
Redshift, and so on
 Inherit potentially same application
performance characteristics
 You don’t get to retire much technical debt
Retain Retire Rehost Replatform Refactor
Rearchitect
(Replace)

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Best practices for Rehost
• Utilize AWS and/or partner tools for increased velocity of your
migration initiative
• Set up Migration Factory with AWS/partner help
• Evaluate and understand your infrastructure environment
• Challenge yourself to improved architecture
• Exercise migrations before doing a cutover
Retain Retire Rehost Replatform Refactor
Rearchitect
(Replace)
AWS Server
Migration Service
(AWS SMS)

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Replatform
Physical Machine/Virtual Machine Image
App Binary
Operating System Files
Disk Volumes
Disk Drives
Memory
NIC
User Data
EC2
New Disk Volumes
Fresh New OS
App Binary User Data
Replatform
• Changing the OS or
DB engine
• Upgrading to the
latest release of an
application
• Upgrading the OS
from Windows 2003
to Windows
2008/2012
• Upgrading from
Oracle 8 to Oracle 11
Retain Retire Rehost Replatform Refactor
Rearchitect
(Replace)

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Replatform
ConsPros
 Option to use cloud services that are close to
existing infrastructure without requiring code
change, for example, RDS, Amazon Aurora,
Amazon EFS, Amazon WorkSpaces
 No dependency on OS, hypervisor or
underlying physical hardware platform
 Migrating to newer platform/OS/DB
 Opportunity to utilize modern OS/DB
features/functionality
 Automated tools assisted option avaialble in
some cases
 Some Replatform projects may be time-
consuming and costlier
 Might require both the existing and new
environment to run in parallel
 Requires additional planning and coordination
Retain Retire Rehost Replatform Refactor
Rearchitect
(Replace)

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Best practice for Replatform
• Evaluate code dependencies on OS
• Identify any modifications required in the code to port it on a
new OS
• Evaluate if porting would require any functionality trade-offs
• Communicate trade-offs with user base and partners
• Wherever possible, break up each functional component and
test them individually
• Consider hybrid environment and plan your migration
appropriately
• If environments are running in parallel, consider DNS switch
method post successful testing
Retain Retire Rehost Replatform Refactor
Rearchitect
(Replace)
AWS Database
Migration Service
(AWS DMS)

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Refactor
Physical Machine/Virtual Machine Image
App Binary
Operating System Files
Disk Volumes
Disk Drives
Memory
NIC
User Data
EC2
New Disk Volumes
New Operating System
App Binary User DataRefactor
• Changing middleware
• Recoding application
components
• Changing application
code to utilize cloud
native feature for
performance, scaling,
agility
Retain Retire Rehost Replatform Refactor
Rearchitect
(Replace)

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Refactor
ConsPros
 Application with a new lifeline, utilizes cloud
native features
 Increased efficiency, agility at improved cost
 Refactor strategy is application code, OS,
hypervisor and hardware agnostic
 Flexibility in porting and globalization
 Adaptive to modern consumer needs
 Better customer experience
 Could be complicated
 Requires a very good understanding of all
aspects of the application, compliance,
regulatory, security, code, design, and so on
 Could be expensive
 Migration timelines could be extended
 Additional resource requirement by the
business
Retain Retire Rehost Replatform Refactor
Rearchitect
(Replace)

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Best practice for Refactor
• Scope your Refactoring initiative to a desired business outcome, don’t
make it a reengineering project
• Make sure your code is working as expected and baseline current
functionality and features
• Make sure you have documented test procedures (and tools) for regular
testing after each component of your code is refactored
• Consider this as an opportunity to introduce good CI/CD practice and
tools, this would allow quick development, testing, rollout and rollback
• Break each refactoring down into small project, ensuring the delivered
code matches the desired functionality
• Use automated refactoring tool if there is one available for your use
case; for example, if your application is C++, you might be able to use
Lint, Visual Assist, Visual Studio
PaaSLane
Retain Retire Rehost Replatform Refactor
Rearchitect
(Replace)

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Rearchitect (Replace)
Physical Machine/Virtual Machine Image
App Binary
Operating System Files
Disk Volumes
Disk Drives
Memory
NIC
User Data User DataRearchitect
$aaS on
Hosted Solution
• Changing from RISC to x86
• Changing application
components
• Rebuilding application
architecture
• Replacing the application
with a SaaS offering or COTS
product
• Purchasing a cloud-
compatible license
Retain Retire Rehost Replatform Refactor
Rearchitect
(Replace)

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Rearchitect (Replace)
ConsPros
 Eliminating dependency on custom hardware
or proprietary technology platforms
 With Replace strategy, no infrastructure to
maintain
 Pay for what you use with SLAs
 Careful evaluation of partners/vendors
required
 Some Rearchitect use cases grow in time and
effort, covering Replatform, and Refactor
 Data migration still required, even if Replace is
the strategy
Retain Retire Rehost Replatform Refactor
Rearchitect
(Replace)

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Best practice for Rearchitect (Replace)
• Evaluate your options, not just from technical functionality perspective, but also
consider integrations with partners, financial viability, and security/compliance or
regulatory requirements
• Build and run in parallel and identify options to keep data between the on premise
and newer system in sync
• Test functionalities in batches; benefits vs. sign-up vs. payroll and so on
• Identify user base that will be testing each functional component of the new
system, migrate in batches as well
Retain Retire Rehost Replatform Refactor
Rearchitect
(Replace)

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Comparing cloud migration strategies
All dimensions of time, cost and agility are relative to migration strategies presented on this slide
RehostRetain Retire Replatform Refactor
Time
Cost
Agility
Rearchitect
(Replace)
Balanced Rewarding

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Case Study

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Who is Scholastic?

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Who is Scholastic?
• Our mission: To encourage the intellectual and personal
growth of all children, beginning with literacy
• Started in 1920 with a single magazine
• The largest publisher and distributor of children’s books in the
world
• 165 countries, 45 languages
• A leading provider of educational materials in K–8

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Strategic things that matter
• Costs
• Uncertainty
• Flexibility
• Risk
• Scale
• Organization
• Strategy and reputation

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Key cost factors
• Current costs
• Like for like costs
• Ideal architecture costs
• Pain point costs
• Transition costs
• Opportunity costs

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Analysis approaches
• Retain or Rehost: macro analysis
• Replatform, Rearchitect: architectural analysis
• Rehost, Refactor, Rearchitect:
• Cost avoidance, feature/scale requirements
• Retire, Rearchitect, Refactor:
• Business alignment
• Lifespan

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Scholastic’s migration mantras
• Everything must go!
• One step at a time
• Find one win
• Improve one thing
• Do or do not, there is no try
• When in doubt, move it
• In the cloud, incremental improvement == $

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Scholastic: Retain (Revisit)
• Our example: e-commerce platform
• Why:
• Recent infrastructure investment
• Older technology with few cloud examples
• Proprietary third party software, no obvious support
• Limited depth of expertise in-house
• Limited lifespan
• Cost and risk of moving >> leaving in place
• Limited value in moving
• Outcome: left in place for 2+ years until retired

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Scholastic: Rehost <-> Replatform
• Our example: marketing website infrastructure
• Why:
• Status quo was not viable
• Technologies very well supported by AWS
• Strong in-house team
• Low risk migration path
• Lots of independent pieces, easily testable.
• Cost and risk of moving < leaving in place.
• Outcome: migration + upgrades over 3-month span

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Scholastic: Rearchitect
• Our example: digital platform
• Why:
• Status quo was not viable
• Desire for investment
• Strong future product growth
• Strong development team
• Good architectural and service fit
• Outcome: Radical cost and performance improvements

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Scholastic: Refactor (+ Replatform)
• Our example: identity services
• Why:
• General architecture was stable
• Relatively small changes
• Good match for AWS
• Obvious and self-contained pain points
• Strong development team
• Status-quo at breaking point
• New solution available
• Outcome: launched May, 10x performance benefits, 5–
10x reliability/recovery improvement

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Scholastic: Retire
• Our example: legacy web products
• Why:
• EOL technology
• No clear migration path (cloud or other)
• No clear refactoring path
• No clear replatform option
• No funding source or clear ROI horizon
• Overlap with other enterprise options
• Outcome: Almost all legacy technologies retired. Some
product lines retired.

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AWS-Provided Migration Tools
Simplify the Journey
Data Transfer
S3 Transfer
Acceleration
AWS Storage
Gateway
AWS Snowball
AWS Direct
Connect
Amazon Kinesis
Firehose
Post Migration
Validation
CloudWatch
Access partner
tools
AWS Marketplace
Server and DB
Migration
AWS Server
Migration Service
AWS Database
Migration Service
VMWare Cloud on
AWS
Planning
AWS Application
Discovery Service
AWS Architecture
Center

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What’s Next?
Application portfolio migration
Operate and
OptimizeDiscover Plan
Migrate and
Validate
Better understand
your application
portfolio
Streamline app
migration planning
and tracking
Reduce time spent
determining current
status
More easily view
migration progress
Application discovery, planning, and migration tracking in one place

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Thank you!

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Remember to complete
your evaluations!

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Related Sessions
ENT218 - Simplify Cloud Migration with AWS Server Migration Service
ENT312 - Develop Your Migration Toolkit
ARC316 - Hybrid IT: A Stepping Stone to All-In
ARC314 - Enabling Enterprise Migrations: Creating an AWS Landing Zone
For more information, please visit
https://aws.amazon.com/migration/partner-solutions/