The document discusses Xero's infrastructure for scaling their cloud-based accounting software. It describes their use of a multi-tenant architecture, Microsoft technology stack, and SQL Server database. It also summarizes Xero's operational support systems and decision to use Rackspace for global hosting due to their fanatical 24/7 support and feeling of being part of the team.

1. Delivering the Infrastructure for Scale Rod Drury, CEO, Xero www.xero.com

2. Research and Development Platform Vendor Picking winners High performance, scalability, maintainability, security, access to resources Global Hosting Global from day 1 Centralised database, fast from anywhere in the world Application Scale for competitive advantage Single instance, multi-tenanted, multi-user, plug in modules (e.g. tax), separation of UI, testable, debuggable, performance monitoring, role based security Operation Support Systems Server runs the business Build or buy, integration, logical separation from application, topology, ease of management, scale globally Teaming model Multi-disciplined team Design led, customer driven, product management, program management, QA

3. Our stack Development environment Microsoft Visual Studio 2008, Virtualisation for internal servers & QA Rendering framework XSLT, Ext.js Data Access LLBLGen pro Runtime platform ASP.Net with custom architecture, WCF Database SQL Server 2005 Enterprise Edition Database Server Windows Server 2003 x64 App Server Windows Server 2003 Hardware 23 servers, 8 for production, load balancing for web servers, clustering for database servers

4. Operational Systems Support (OSS model)

5. Global Hosting Model

6. Hosting partner engagement Model Co-location vs Full managed service? Selection Process Developed checklist Shortlisted 4 providers Site visits and consistent interview process Evaluation and selection Contract negotiation Implementation 4 weeks from contract to go live Ongoing operations

7. Why Rackspace Impressed by their research and understanding of our business Fanatical support - really Dedicated support team with specialist available 24x7 Online ticket management superb Often less than 10 minute turnarounds Complete partner No surprises Consulting advice freely given Feels like they are part of our team