Scalability
“Scalability” 是架构非功能需求之一,涉及吞吐、延迟、成本曲线。常区分 scale up(垂直)与 scale out(水平);良好 scalability 意味着增加资源带来近似线性的容量提升。
- “Load tests measured scalability up to five times normal traffic.” (压测衡量了高达正常流量五倍时的可扩展性。)
- “Sharding improved database scalability for large tenants.” (分片提升了大租户场景下的数据库可扩展性。)
- “Scalability planning should include cost per additional user.” (可扩展性规划应包含每新增用户的成本。)
scalable + -ity,scale 表规模,-ity 表抽象性质。
“scalable” + “-ity”:可扩展这一特性。
CAP 定理、Amdahl 定律与 scalability 讨论紧密相关;过早优化 scalability 不如先验证产品市场契合。
- 固定搭配: “horizontal scalability” (水平可扩展性), “scalability bottleneck” (扩展瓶颈), “scalability test” (扩展性测试)
- 形容词: scalable
scalable 的名词形式——ability to scale,即 scalability。
“Poor scalability showed up as rising p99 latency long before the servers maxed out CPU.” (可扩展性不足表现为 p99 延迟上升,远早于 CPU 打满。)