Updated on 2024-06-12 GMT+08:00

Performance Metrics

CDN provides stable acceleration and relieves pressure on origin servers. You can view performance metrics before and after CDN is used to check the acceleration effect.

Common Metrics

The following table lists CDN common metrics.

Metric

Description

Latency

Total time required for uploading or downloading a file.

Packet loss rate

Ratio of the number of lost packets to the number of sent packets.

Origin pull ratio

This ratio includes the origin request ratio and pull traffic ratio.
  • Origin request ratio = Requests with cache misses/All requests on CDN PoPs. A cache miss occurs when the content is not cached, the cache of the content (cacheable) has expired, or the content cannot be cached.
  • Pull traffic ratio: Origin traffic is generated when CDN PoPs request content from origin servers. Pull traffic ratio = Pull traffic/(Pull traffic + Traffic generated by user requests). A lower ratio indicates a better performance.

Cache hit ratio

Cache hit ratio includes request hit ratio and traffic hit ratio. A higher cache hit ratio indicates a better performance.

  • Cache hit ratio = Number of requests that hit caches/Number of total requests
  • Traffic hit ratio = Traffic generated when CDN PoP caches are hit/Total request traffic

    Total request traffic = Traffic generated when CDN PoP caches are hit + Traffic generated during origin pull

    NOTE:

    The traffic hit ratio indicates the load on the origin server. A lower traffic hit ratio means a larger origin pull traffic, which leads to a larger output traffic and higher bandwidth consumption on the origin server.

  • When CDN is used, the latency, packet loss rate, and origin pull ratio decrease, whereas the cache hit ratio increases. However, the acceleration performance varies between service scenarios and types, even if the CDN configuration is the same. Therefore, this topic provides only qualitative indicators for your references.
  • If you do not use CDN, the origin pull ratio is 100% and the cache hit ratio is 0.

Acceleration Case

This test uses the universal test method in the industry. The service provider is Tingyun. Test objects are Huawei Cloud OBS buckets and Huawei Cloud CDN. Test carriers are China Unicom and China Telecom.

  • Latency

    Unit: second

  • Availability

    The availability of OBS buckets and CDN is 100%.

  • Detailed data

    Time

    OBS

    CDN

    Latency (s)

    Availability (%)

    Monitoring Sites

    Latency (s)

    Availability (%)

    Monitoring Sites

    Nov 18 15:12

    1.149

    100

    57

    1.227

    100

    62

    Nov 18 16:12

    1.075

    100

    167

    0.616

    100

    169

    Nov 18 17:12

    0.867

    100

    172

    0.433

    100

    171

    Nov 18 18:12

    0.7

    100

    169

    0.321

    100

    169

    Nov 18 19:12

    0.94

    100

    173

    0.534

    100

    173

    Nov 18 20:12

    1.119

    100

    176

    0.765

    100

    176

    Nov 18 21:12

    0.841

    100

    175

    0.609

    100

    176

    Nov 18 22:12

    0.983

    100

    181

    0.682

    100

    180

    Nov 18 23:12

    0.923

    100

    173

    0.58

    100

    174

    Nov 19 00:12

    1.08

    100

    184

    0.737

    100

    184

    Nov 19 01:12

    1.147

    100

    180

    0.812

    100

    178

    Nov 19 02:12

    1.29

    100

    181

    0.853

    100

    183

    Nov 19 03:12

    1.041

    100

    177

    0.617

    100

    176

    Nov 19 04:12

    1.339

    100

    184

    0.997

    100

    184

    Nov 19 05:12

    1.035

    100

    179

    0.74

    100

    179

    Nov 19 06:12

    0.865

    100

    180

    0.566

    100

    181

    Nov 19 07:12

    1.258

    100

    176

    1.071

    100

    175

    Nov 19 08:12

    1.338

    100

    170

    0.878

    100

    170

    Nov 19 09:12

    1.085

    100

    155

    0.705

    100

    155

    Nov 19 10:12

    1.213

    100

    168

    0.822

    100

    169