Varnish和ESI，性能如何？

发布于 2024-11-06 12:49:23 字数 116 浏览 5 评论 0原文

我想知道现在ESI模块的性能如何？我在网上读过一些帖子，说清漆上的 ESI 性能实际上比真实的慢。

假设我有一个包含超过 3500 个 esi 包含的页面，这会如何执行？ ESI是为这种用途而设计的吗？

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治碍 2024-11-13 12:49:24

我们使用 Varnish 和 ESI 将子文档嵌入到 JSON 文档中。基本上，我们的应用程序服务器的响应如下所示：

[
  <esi:include src="/station/best_of_80s" />,
  <esi:include src="/station/herrmerktradio" />,
  <esi:include src="/station/bluesclub" />,
  <esi:include src="/station/jazzloft" />,
  <esi:include src="/station/jahfari" />,
  <esi:include src="/station/maximix" />,
  <esi:include src="/station/ondalatina" />,
  <esi:include src="/station/deepgroove" />,
  <esi:include src="/station/germanyfm" />,
  <esi:include src="/station/alternativeworld" />
]

包含的资源本身就是完整且有效的 JSON 响应。所有电台的完整列表约为 1070 个。因此，当缓存处于冷状态并且完整的电台列表是第一个请求时，清漆会在我们的后端发出 1000 个请求。当缓存很热时，ab 看起来像这样：

$ ab -c 100 -n 1000 http://127.0.0.1/stations
[...]

Document Path:          /stations
Document Length:        2207910 bytes

Concurrency Level:      100
Time taken for tests:   10.075 seconds
Complete requests:      1000
Failed requests:        0
Write errors:           0
Total transferred:      2208412000 bytes
HTML transferred:       2207910000 bytes
Requests per second:    99.26 [#/sec] (mean)
Time per request:       1007.470 [ms] (mean)
Time per request:       10.075 [ms] (mean, across all concurrent requests)
Transfer rate:          214066.18 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:        1   11   7.3      9      37
Processing:   466  971  97.4    951    1226
Waiting:        0   20  16.6     12      86
Total:        471  982  98.0    960    1230

Percentage of the requests served within a certain time (ms)
  50%    960
  66%    985
  75%    986
  80%    988
  90%   1141
  95%   1163
  98%   1221
  99%   1229
 100%   1230 (longest request)
$

100 次记录/秒看起来不太好，但请考虑文档的大小。 214066Kbytes/sec 使 1Gbit 接口过饱和。

使用热缓存 ab (ab -c 1 -n 1 ...) 的单个请求显示 83ms/req。

后端本身是基于redis的。我们在 NewRelic 中测量的平均响应时间为 0.9 毫秒 [原文如此]。重新启动 Varnish 后，第一个带有冷缓存的请求 (ab -c 1 -n 1 ...) 显示 3158ms/rec。这意味着在生成响应时，Varnish 和我们的后端每个 ESI 包含大约需要 3 毫秒。这是一个标准的核心 i7 披萨盒，有 8 个核心。我是在满载的情况下测量的。我们以这种方式每月提供大约 150mio 请求，命中率为 0.9。这些数字确实表明 ESI-includes 是串行解析的。

在设计这样的系统时，您必须考虑的是 1) 当缓存冷时，您的后端能够在 Varnish 重新启动后承担负载，2) 通常您的资源不会一次性全部过期。对于我们的站点，它们每隔一小时就会过期，但我们会在过期标头中添加一个最多 120 秒的随机值。

希望有帮助。

We're using Varnish and ESI to embed sub-documents into JSON documents. Basically a response from our app-server looks like this:

[
  <esi:include src="/station/best_of_80s" />,
  <esi:include src="/station/herrmerktradio" />,
  <esi:include src="/station/bluesclub" />,
  <esi:include src="/station/jazzloft" />,
  <esi:include src="/station/jahfari" />,
  <esi:include src="/station/maximix" />,
  <esi:include src="/station/ondalatina" />,
  <esi:include src="/station/deepgroove" />,
  <esi:include src="/station/germanyfm" />,
  <esi:include src="/station/alternativeworld" />
]

The included resources are complete and valid JSON responses on their own. The complete list of all stations is about 1070. So when the cache is cold and a complete station list is the first request varnish issues 1000 requests on our backend. When the cache is hot ab looks like this:

$ ab -c 100 -n 1000 http://127.0.0.1/stations
[...]

Document Path:          /stations
Document Length:        2207910 bytes

Concurrency Level:      100
Time taken for tests:   10.075 seconds
Complete requests:      1000
Failed requests:        0
Write errors:           0
Total transferred:      2208412000 bytes
HTML transferred:       2207910000 bytes
Requests per second:    99.26 [#/sec] (mean)
Time per request:       1007.470 [ms] (mean)
Time per request:       10.075 [ms] (mean, across all concurrent requests)
Transfer rate:          214066.18 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:        1   11   7.3      9      37
Processing:   466  971  97.4    951    1226
Waiting:        0   20  16.6     12      86
Total:        471  982  98.0    960    1230

Percentage of the requests served within a certain time (ms)
  50%    960
  66%    985
  75%    986
  80%    988
  90%   1141
  95%   1163
  98%   1221
  99%   1229
 100%   1230 (longest request)
$

100 rec/sec doesn't look that good but consider the size of the document. 214066Kbytes/sec oversaturates a 1Gbit interface well.

A single request with warm cache ab (ab -c 1 -n 1 ...) shows 83ms/req.

The backend itself is redis based. We're measuring a mean response time of 0.9ms [sic] in NewRelic. After restarting Varnish the first request with a cold cache (ab -c 1 -n 1 ...) shows 3158ms/rec. This means it takes Varnish and our backend about 3ms per ESI include when generating the response. This is a standard core i7 pizza box with 8 cores. I measured this while being under full load. We're serving about 150mio req/month this way with a hitrate of 0.9. These numbers suggest indeed that the ESI-includes are resolved in serial.

What you have to consider when designing a system like this is 1) that your backend is able to take the load after a Varnish restart when the cache is cold and 2) that usually your resources don't expire all at once. In case of our stations they expire every full hour but we're adding a random value of up to 120 seconds to the expiration header.

Hope that helps.

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