Architectural Impact of SaaS

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Architectural Impact of SaaS

• Eric Nelson
• Microsoft

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Basic SaaS Maturity Model
1. ad-hoc /custom
2. configurable single tenant
4. configurable multi tenant (scalable)
3. configurable multi tenant
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Three Headed Monster
Scaleable
Configurable

Multi-Tenant Efficient
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• multi-tenant data architectures

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vs
share
isolate
business model (can I monetise?) architectural
model (can I do it?) operational model (can I
guarantee SLAs?) regulatory constraints (can we
share data?)
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separate database per tenant

• Approach
• Meta data identifies database instance for each
  tenant
• Advantages
• Easy to implement data model extension
• Easy to restore tenant data
• More security isolation
• Tradeoff
• Number of tenants per database server is low
• Higher management, backup cost and database
  server infrastructure costs
• When to use
• When tenant has specific database isolation
  requirements

Tenant A
Tenant B
Tenant C
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same database, separate schema

• Approach
• Each tenant gets their own group of tables in the
  same database.
• Advantages
• Easy to implement data model extension
• Moderate security isolation
• Better tenant scale per server
• Tradeoff
• More difficult to restore tenant data
• When to use
• Number of tables for the app is small (100s)
• Scale per server is important
• OK to co-locate tenant data in same database

Tenant A
Tenant B
Tenant C
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same database, same schema

• Approach
• All tenants use the same set of tables in the
  same database.
• Advantages
• Better tenant scale per server
• Cost of management and backup is lower
• Tradeoff
• Difficult to restore tenant data
• Harder to implement data model extension
• When to use
• Scale per server is important
• OK to co-mingle tenant data in same database

Tenant B
Tenant A
Tenant C
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• single instance, mult-tenant

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• Configurable

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meta-data
UI/branding workflow and rules data model
extensions access control other domain specific
considerations

• considerations

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meta-data

• UI/branding

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meta-data

• workflow/rules

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meta-data

• data model extensions

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meta-data

• access control

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Summary

• Plenty of stuff to get right ?
• Plenty of stuff to get wrong ?
• It is not easy to do well...