How to deploy a 3-tier fully reliable multi-site application.
The following notes give an outline of how to create an environment which meets stringent Production Suitability criteria - i.e.
- Scalable
- Stable
- Reliable
- Recoverable
- Secure
- Resilient
- Supportable
However, the provision of an adequate Production-Worthy solution is not just a matter of technology. People and Processes all contribute to making the solution fulfil its long-term goals. Therefore, the following sections refer not only to the technical aspects of a typical solution, but also the "soft skills" involved.
Given this sort of approach, a company would be able to put into place a solution which would not only work, functionally, but would also serve the long-term interests of the company - thereby maximising the Return on Investment.
Multi-Site Deployment
The first aspect which we need to emphasise is that our (mythical) company's data-centre, itself, is a Single Point of Failure. 20KM limit
Multiple Firewalls
We assume that the first level is already breached..
IP re-direction
Always have logical - not physical - IP addresses. Level 3 switches. Altheon, BigIP.
The "farm" of web-servers
Ensure the data is common.
Protecting the Business Logic
The key to your business.
Access Control
Think of hacking before you start.
Parallel Database Environment
2-phase commit or asynchronous replication ?
Cross-site Replication
EMC, DRM
Monitoring and Capacity Planning
How many hits
Service Management
Plan your outages on day one.
24*7 Support
Not an afterthought.
Processes and Procedures
60% of problems due to human activities - not the operating system.
