SE401:Group33:Research

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Stuff to look into

• Existing stress testing/load simulation tools (to be used to test our implementation)
• Scalable software
  • What is it
  • What are the aims
  • What existing infrastructure is there
    • Is it any good?
  • Apps currently running on AWS
  • Automatically scaling software

• How other people have developed scalable software
  • Approaches, techniques, ideas, existing implementations

• Existing tools to automatically scale applications hosted on AWS
  • Approaches
  • Limitations
  • Is the main metric processor utilisation?
    • Is processor utilisation a good metric?

• What are good metrics to determine the need to start/stop application servers to deal with high/low number of requests

Useful resources

AWS Home
AWS Developer Forums
List of Engineering databases
IEEE Xplore database
Inspec database
ACM database
Computer Index Australasia database

Results

Papers

• Developing Web Services
• Adaptive TTL schemes for Load Balancing
• Application Layer Casting - Server Selection of a replicated web service
• Vision for Autonomic computing
• Autonomic computing manifesto

Other findings

• If an instance fails, all the data stored on it's hard drive is lost, irretrievably. This means a method of persistent storage must be used. Look at http://www.persistentfs.com/documentation/Release_Notes PersistentFS]
• It is currently not possible to create fail safe load balancing in ECS. You cannot guarantee that an instance will run, so you need a dedicated load balancing machine outside the cloud. "Unfortunately, one major drawback with EC2 is that it is not possible to architect a server-side load balancing solution that doesn’t have a single point of failure. Many web applications hosted on EC2 use a single EC2 instance with dynamic DNS to load-balance requests to a particular domain. If the instance that provides the load balancing fails, the whole system can become unavailable until the dynamic DNS maps the domain to another EC2 instance." ref. Therefore look at client side load balancing as describe in ref
• A server side load balancer might be HAProxy, if server side load balancing was needed
• RightScale do what we want to do, plus more, and charge mega mega bucks for it. << Wont be nearly as good as our tool. We will have a more robust system, we wont charge mega bucks... or will we, and our system will be more configurable >>
  • http://wiki.rightscale.com/2._References/Monitoring_System
• http://code.google.com/p/cloudtools/

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