Skip to content

Latest commit

 

History

History
45 lines (30 loc) · 1.72 KB

Week4-Day1.md

File metadata and controls

45 lines (30 loc) · 1.72 KB
Raw
layout title sched-activation
course
Week 4, Day 1 (Monday Jan 27)
class="active"

In-class exercise

List the biggest unknowns or risks you see for yourself or your team in Assignment 2. Items to think about:

In Part 1:

  • How will you format the messages from the server to the worker?

In Part 2:

  • How will you set up an EC2 instance so that it will start the worker process when CloudWatch starts a new instance?
  • How will you force the load high enough to require that new instances be started?

Reducing latency of service requests

  • The SLA for our service might be legally binding or a market requirement.

  • Variable latencies are inevitable.

  • How to keep our latencies within our (binding or best-effort) SLA?

  • Ways to reduce latency of a single request:

    • Hedge the request: Wait a bit, request a duplicate, cancel second on first reply
    • Tie the request: Issue two requests, cancel second once first begins

Reading guide to next class

Read [{{ site.data.bibliography.cavage2013.title }}]({{ site.data.bibliography.cavage2013.url }}), up to but not including "Messaging", p. 67.

Note that (as he says on p. 85), his use of "distributed system" is synonymous with how we use "cloud".

Key point:

While much of the discussion, literature, and presentations focus on the en vogue technologies such as Paxos, Dynamo, or MapReduce … the reality of building a large distributed system is that many “traditional” problems are left unsolved by off-the-shelf solutions, whether commercial or open source. (p. 64)

You don't need to pay close attention to:

  • The opening pages (pp. 63--64), giving two reasons for using a distributed system, are background.