Saturday, August 28, 2021

Architecture design patterns

I came across this great article and could not agree more with these patterns discussed by the author. No matter which names we give to these patterns, but they are really essential to a distributed and complicated system for being resilient to avoid cascading failures.

Bulkhead resilience pattern enables developers to design a system with multiple, independent subsystems and services running in their own private machines or containers. Build highly loose coupling microservices.

Backpressure is a resilience approach that configures individual application systems and services to autonomously push back incoming workloads that exceed its current throughput capacity. This pattern can often help manage throughput naturally, without the need to pile an unfair or unregulated number of requests on any single component.

The circuit breaker pattern an stop temporary outages from becoming cascading failures that run rampantly across large swaths of the software stack. In the event of overloads, the circuit opens and will reject any new requests and put a halt to the pending message queue. When workload stress levels and throughput drop back down to an acceptable level, the circuit closes and starts accepting requests again.

Batch processing of records usually builds up abrupt, performance-dampening spikes of stress on services, databases and all other related components. Batch-to-stream pattern forces it to submit to load balancers and trigger the appropriate remediating mechanisms when throughput exceeds acceptable rates. Such workload throttling technique can safeguard a consistent rate of push, ensure that the load balancer distributes jobs appropriately.

When a component or service fails completely, graceful degradation pattern helps to maintain continuity using a fallback mechanism that allows alternative components to automatically pick up.

Sunday, August 1, 2021

读书笔记 - Alone on the wall

Alex Honnold and David Roberts wrote this book "Alone on the wall" to recount the most astonishing achievements of Honnold's extraordinary life and career, brimming with lessons on living fearlessly, taking risks, and maintaining focus even in the face of extreme danger. 

On June 3, 2017, Alex Honnold became the first person to free solo Yosemite's El Capitan. The followings are reading notes of this book.

  • Free soloing a big wall is all about preparation.
  • He's pushed the most extreme and dangerous form of climbing far beyond the limits of what anyone thought was possible.
  • Free soloing means climbing without a rope, a partner, or any hardness (pitons, nuts, cams, bolts) to attach oneself to the wall.
  • If you fall, you die.
  • George Leigh Mallory response in 1923 to climb Everest "Because it is there".
  • Free climbing means that the leader was his protection only to safeguard a fall.
  • Rock routes climbed free are rated on a scale of difficulty, called the Yosemite Decimal System (YDS) that ranges from 5.1 to 5.15.
  • The hardest climbs in the world are rated 5.15c.
  • Visualizing everything that could happen.
  • What's the point in having an amazing vehicle if you are afraid to drive it?
  • The universe shrinks down to me and the rock you don't take a single hold for granted.
  • Climbing down is almost always harder than climbing up.
  • - the world's best rock climbing guide info
  • Doubt is the biggest danger in soloing. As soon as you hesitate, you're screwed.
  • Yosemite triple crown: three of the park's biggest walls: Mt Watkins, El Capitan, Half Dome.
  • We will all continue climbing in the ways that we find most inspiring, whether or not we're sponsored, the mountains are calling, and we must go.
  • I could suddenly travel full-time without feeling like I had to come back for something.
  • I considered a potential free solo of El Cap to be the holy grail of climbing.
  • Being uncomfortable was a lot better than being incapable.
  • The season was over, but I was more motivated than ever.
  • I knew it was possible. I knew that I could do it.
  • That moment made me hope that I will have even a fraction of his enthusiasm for climbing when I'm in his age, or just his passion for life.
  • It was a good reminder to stay humble and keep asking for help. Each of my friends had something to teach me or remind me on the route.
  • Real soloing rquires me to climb exactly as I normally would with a rope, it's climbing that has only one solution.
  • I was fully prepared and knew exactly what to do. It was the time for execution.
  • I was overwhelmed with happiness and gratefulness.