Cloudflare Cache Reserve Walkthrough and Demo

Summary

此视频分享了如何使用Cloudflare的缓存预留功能来提高网站内容的缓存命中率。它首先介绍了Cloudflare CDN的基本工作原理,然后重点讨论了缓存预留的功能和流程。演示了如何在Cloudflare仪表盘中启用该功能,并通过缓存数据到Cloudflare的持久化存储桶来进一步减少服务器负载并降低成本。最后,视频还展示了如何使用Cloudflare的日志和分析功能,更好地了解缓存命中情况和缓存预留的使用情况。

Takeaways

• 💻 Cloudflare CDN 可自动导入当前 DNS 提供商记录,并为用户提供 Cloudflare DNS 服务器使用。
• 🏃 Cloudflare CDN 提供两种加入方式:更改权威 DNS 或部分 CNAME 设置。
• 🗃️ Cloudflare 会根据文件扩展名缓存可缓存内容,当缓存内容过期或手动清除时,会从源服务器重新获取。
• 🌳 缓存分为多层,仅顶层数据中心能从源服务器获取内容。智能分层缓存拓扑可以改善带宽效率和减少源服务器压力。
• 🔄 当发生缓存未命中时,Cloudflare 首先检查持久存储桶中的内容,再从源服务器获取,进一步提升缓存率。
• ⏰ 对于过期或被清除的内容,Cloudflare 会先检查持久存储桶,若内容仍存在则从存储桶获取,降低从源服务器获取频率。
• 🚀 演示中网站部署在第三方云提供商,使用自动流量模拟访问。Cloudflare 控制面板可展示缓存状态和持久存储使用情况。
• 📝 演示中缓存命中率从80%提升至92%,接近100%的优化目标。Cloudflare 提供页面规则微调缓存行为。
• ⌛ 用户可自行设置资源缓存时间,覆盖源服务器设置的 TTL。日志推送功能支持记录来自持久存储的请求数据。

Q & A

什么是Cloudflare CDN?

Cloudflare CDN(内容分发网络)是一个全球分布的网络基础设施,可以加快网站内容的传输,并提高整体性能。它通过缓存网站内容并将其存储在靠近用户的数据中心,从而减少了从源服务器检索内容的需求,从而降低了延迟并提高了网站的可用性。

如何开始使用Cloudflare CDN?

要开始使用Cloudflare CDN,您只需在仪表板上单击"添加站点",输入您的域名即可。Cloudflare可以自动从您现有的DNS提供商导入DNS记录。然后,您将获得Cloudflare的名称服务器,可用于更改授权DNS,使用Cloudflare的DNS和CDN。如果您不想更改主DNS,也可以通过部分CNAME设置使用Cloudflare CDN。

请简要解释一下Cloudflare CDN的基本流量流?

当用户发出HTTP请求时,最接近用户的Cloudflare数据中心将处理该请求。如果请求的URL与可缓存文件扩展名列表匹配,则Cloudflare将从缓存中提供该资源(如果存在)。否则,Cloudflare会尝试从多个网络位置的缓存中获取内容并提供服务。如果内容仍然存在于Cloudflare的缓存中,则会尝试从源重新验证内容。如果资源不在缓存中,Cloudflare会从源请求资源以填充缓存,然后将响应发送给发起请求的客户端。

Cloudflare Cash Reserve是什么?

Cloudflare Cash Reserve是一种功能,可以进一步提高缓存命中率,将所有可缓存文件自动存储到Cloudflare的持久对象存储桶中。当发生缓存未命中时,Cloudflare将首先在这些存储桶中查找内容,而不是直接从源检索。Cash Reserve充当了终极高级层,有助于减少从源获取内容的需求。

使用Cash Reserve后,流量流会有什么变化?

使用Cash Reserve后,当客户端向最近的Cloudflare数据中心发出请求时,如果内容在该数据中心和高级层数据中心都没有被缓存,高级层数据中心将先在Cash Reserve中查找内容,而不是立即从源请求。如果内容存在于Cash Reserve,则从那里检索。否则,Cash Reserve将从源请求内容。响应将被缓存在Cash Reserve、高级层和低级层数据中心。下次请求相同内容时,如果在低级层和高级层的缓存都失效,Cloudflare会先在Cash Reserve中查找,如果存在,则从那里提供服务并缓存在其他层。

Cash Reserve使用Cloudflare网络的哪些部分?

Cash Reserve充当了Cloudflare网络中"终极高级层"。当在低级层和高级层数据中心的缓存都失效时,Cloudflare会先查看Cash Reserve,而不是立即从源请求内容。这有助于最小化从源获取内容的需求,从而减少不必要的出口费用。

如何监控Cash Reserve的使用情况?

在Cloudflare仪表板中,您可以查看Cash Reserve中当前存储的数据量、一段时间内使用的总存储量,以及总体的Cash Reserve读写操作数。您还可以查看"总体缓存状态",包括由Cloudflare服务的内容和由源服务的内容。使用分析和日志功能,您可以设置日志推送并包括"Cash Reserve 已使用"字段,以获得有关从Cash Reserve服务的请求和相应内容的更多可见性。

如何在Cloudflare中管理缓存行为?

在Cloudflare仪表板中,您可以"清除缓存"以手动清除缓存(包括Cash Reserve)。您还可以使用"页面规则"来创建更细粒度的缓存行为。在"缓存规则"下,您可以为特定主机名创建规则,以覆盖来自缓存控制标头的TTL设置。这可以在边缘完成,并且为所有资产一次性设置TTL非常方便。

使用Cash Reserve有什么好处?

使用Cash Reserve可以进一步提高缓存命中率,因为当在Cloudflare网络的其他层发生缓存未命中时,内容将首先从Cash Reserve检索。通过最小化从源请求内容的需求,它有助于减少延迟,减少带宽使用,降低源服务器负载,使网站的运营成本更低。从而提供更好的整体性能。

什么时候会发生缓存未命中?

有两种情况会导致缓存未命中:1)有意的 - 缓存TTL过期或内容被手动清除;2)无意的 - 由于Cloudflare的LRU(最近最少使用)算法来优化存储空间,不常访问的内容可能会被清除。在这两种情况下,Cash Reserve都可以作为最后一道防线,提高缓存命中率。

Outlines

00:00

📚 CloudFlare CDN入门和流量流程

段落1介绍了CloudFlare CDN的基础知识,如何从仪表板开始使用,以及通过CloudFlare CDN的流量流程。当用户请求某个资源时,最近的数据中心会处理该请求。如果资源可缓存,则从缓存中提供。否则,从源服务器获取资源并缓存。CloudFlare使用分层缓存拓扑结构,包括上层和下层数据中心,以控制带宽和连接数。智能分层缓存拓扑是所有计划的默认选项。在流量流中,客户端请求到达最近的下层数据中心。如果在下层未缓存,则会检查上层数据中心。如果上层也未缓存,它会从源服务器请求内容并缓存。接下来当另一客户端请求同一内容时,如果上层已缓存,就不需要再从源服务器获取。另外介绍了缓存过期和云朗缓存清除的原因。

05:01

💾 CloudFlare Cash Reserve详解和演示

段落2介绍了CloudFlare Cash Reserve功能以进一步提高缓存命中率。Cash Reserve会自动将所有可缓存文件存储在CloudFlare持久对象存储桶中。在流量流中,当上层数据中心未缓存内容时,会先检查Cash Reserve而不是立即从源请求。如果Cash Reserve有缓存,则返回并缓存在上层和下层数据中心。这一流程大大减少了不必要地从源服务器请求内容。演示部分展示了如何在CloudFlare仪表板中启用Cash Reserve,查看存储使用情况和读写操作数。用于了解在启用Cash Reserve之前和之后的缓存命中率差异。还演示了如何通过缓存规则覆写源服务器的缓存控制头,以及如何记录Cash Reserve使用的日志信息。

Keywords

💡Cloudflare CDN

Cloudflare内容分发网络（CDN）是一种服务，旨在通过全球分布的服务器网络加速网站和网页内容的加载速度。在视频中，讲解者介绍了如何通过Cloudflare CDN轻松开始和上线，强调了其在提高网站性能和减少原始服务器负载方面的重要性。例如，通过自动导入DNS记录和提供Cloudflare的名称服务器，用户可以快速集成Cloudflare CDN到他们的网站。

💡DNS

域名系统（DNS）是互联网的电话簿，将人类可读的网站名称（如example.com）转换为机器可读的IP地址。视频中提到，Cloudflare可以自动从用户现有的DNS提供者那里导入DNS记录，并允许用户使用Cloudflare的DNS作为权威DNS，这是将网站接入Cloudflare CDN的一部分。

💡缓存

缓存是存储临时数据以便快速访问的技术。在视频中，缓存是Cloudflare CDN提高网站性能的关键方法之一。通过缓存可缓存的文件扩展名列表上匹配的HTTP请求，Cloudflare可以从缓存中提供资源，减少对原始服务器的请求。这降低了延迟，节省了带宽，并减轻了服务器的负担。

💡Cache Reserve

Cache Reserve是Cloudflare提供的一个功能，允许将所有可缓存的文件自动存储到Cloudflare的持久对象存储桶中。视频中解释了Cache Reserve如何作为最终的上层缓存层，在发生缓存未命中时，Cloudflare会首先检查这些存储桶，而不是直接从原点请求。这进一步提高了缓存命中率，减少了不必要的出口费用。

💡Tiered Cache

分层缓存是一种优化缓存机制，通过将Cloudflare的全球数据中心网络划分为上层和下层来控制带宽和连接数。视频中提到，只有上层被允许从原点请求内容，并负责将信息分发给下层。这种智能分层缓存拓扑结构默认开启，并为所有计划免费提供。

💡缓存命中率

缓存命中率是衡量缓存系统效率的指标，即从缓存中成功提供请求内容的比例。视频中，通过引入Cache Reserve，讲解者展示了缓存命中率从80%提高到90%以上，显示了Cache Reserve对于提高缓存命中率和优化网站性能的重要性。

💡缓存控制

缓存控制是HTTP头部用来定义页面或其他资源的缓存策略的一部分。在视频中，讲解者讨论了如何通过设置缓存控制时间（TTL）来指示内容何时过时并需要重新验证。此外，用户可以手动清除内容，或者依赖Cloudflare使用最少最近使用（LRU）算法自动优化存储空间。

💡HTTP请求

HTTP请求是客户端（浏览器）和服务器之间通信的一种方式，用于请求网页内容。视频中详细讨论了HTTP请求如何被Cloudflare CDN处理，包括如何根据可缓存的文件扩展名列表匹配和服务请求，以及如何从缓存或原点获取内容。

💡原点

原点是指托管网站内容的服务器。在Cloudflare CDN的上下文中，当缓存中不存在请求的内容时，Cloudflare会向原点发出请求以填充缓存并将响应发送给客户端。视频中提到了原点的重要性，特别是在讨论如何通过减少对原点的请求来优化性能和成本效益。

💡分析和日志

分析和日志提供了关于网站性能和流量模式的重要信息。视频中，讲解者展示了如何使用Cloudflare的分析和日志功能来监控缓存状态、缓存命中率和其他关键指标，以及如何配置日志推送来跟踪和分析从Cache Reserve服务的请求。这些工具对于优化网站性能和用户体验至关重要。

Highlights

云服务商Cloudflare的CDN简介,包括如何开始使用和上手 Cloudflare CDN。

Cloudflare CDN的基本流量流程。

Cloudflare的层级缓存(Tiered Cache)及其智能分层拓扑结构。

何时会发生缓存未命中的情况。

Cloudflare Cash Reserve介绍及其作用。

启用Cash Reserve后的流量流程。

示例网站部署和启用Cash Reserve。

查看Cash Reserve使用情况和数据。

缓存命中率提升情况。

查看缓存详情,包括热门文件类型等。

Purge缓存。

Page规则设置缓存行为。

缓存规则和过期时间覆盖。

外部日志及Cash Reserve使用情况记录。

总结及补充资料链接。

Transcripts

hello my name is humir Ahmed and in this

video I'm going to walk through Cloud

for cash reserve and follow up with demo

I will very briefly discuss some Basics

from cloud for CDN before getting right

into Cash Reserve to provide a better

grasp of how everything fits together

however I'll keep this very minimal so I

can focus on cash Reserve for more

thorough understanding of cloud

vercidian in general and how it works

please see the cloud for CDN reference

architecture in the prior video I did on

cloudflare CDN walkthrough with that

let's get going

first let's talk about how easily you

can get started and onboarded onto

cloudflare CDN

from the dashboard simply click add site

and enter your domain cloud4 can

automatically import your DNS records

from your existing DNS provider and

finally you're given Cloud for name

servers you can use to change your

authoritative DNS so here you're using

cloudford's DNS Azure authoritative DNS

and also onboarded onto cloudflare CDN

now if you don't want to change your

primary or authoritative DNS you can

still use cloudflare CDN by simply doing

a partial cname setup so lots of

flexibility there

so if we look at the very basics of the

traffic flow now first HTTP request is

made closest data center to user handles

the request users HTTP request URL is

matched against the list of cachable

file extensions if the request matches

an extension on the list Cloud first

serves the resource from Cache if

present

second content is fetched from Cache or

origin cloudflare examines its caches in

multiple Network locations for content

and serves it if present if the content

is still in Quad verse cache cloudfare

attempts to revalidate the content with

the origin before serving the response

to the client if the resource is not

present in the cache Cloud Fair requests

the resource from the origin to fill the

cache and the response is then sent to

the client who initiated the request

if cachable content is cached on the

response so cloudflare's cash logic

examines the HTTP response received from

the origin the response is either deemed

cachable and written to disk for use

with the next request for the same

resource or the request is deemed

uncashable

now let's take a look at the traffic

flow with Cloud Fair tiered cache with

smart tiered cache topology enabled as a

reminder tiered cash divides

cloudflare's network of global data

centers into a hierarchy of upper tiers

and lower tiers and in order to control

bandwidth number of connections between

an origin and cloudflare only upper

tiers are permitted to request content

from an origin and are responsible for

Distributing information to the lower

tiers smart tiered cash topology is the

default topology and available for free

for all plans this is also recommended

for most deployments instructing

cloudflare to find the single best upper

tiers for your Origins

benefits here include improved bandwidth

efficiency reduced origin load and

making websites more cost effective to

operate

so when client one sends a request to

the closest data center data center one

here

if the content is not cached the upper

tier data center label data center 3

here is checked if the content is not

cached at the upper tier the upper tier

requests the content from the origin

once their sponsors returned from the

origin the upper tier caches it and

returns a response to the lower tier

which also caches it and returns a

response to the client

now let's say client 2 makes the same

request for the same content to its

closest data center data center too

if the content is not cached to Data

Center too similar to Prior the upper

tier data center is checked however in

this case content was requested prior

via client 1 and the upper tier data

center has the content cached and

Returns the cache content to the lower

tier data center data center 2 which in

turn caches the content and responds

back to the client decreasing latency

saving bandwidth and load on the server

and providing better overall performance

so now that we have a better

understanding of cloud for CDN when does

a cache Miss occur well we have two

scenarios first intentional cash TTL

expired or content purged customers set

cache control time to signify when the

content is out of date and needs to be

revalidated once expired content needs

to be revalidated and may need to be

pulled from the origin if updated

version exists customers can Purge

content manually at any time

second unintentional cloudflare Purge

content due to lru or least recently

used algorithm to optimize storage less

frequently accessed content may be

purged based on lru or how long the

network wants content to remain cached

now this is where Cloud for cash Reserve

can be useful to further increase cash

hit ratio by automatically storing all

cachable files into cloudflare's

persistent object storage buckets

basically cash Reserve acts like an

ultimate upper tier and when there's a

cash Miss cloudflare will first check

these storage buckets before going to

the origin you can see here I've enabled

it and I'll walk through this more in

the demo

so let's look at the traffic flow now

again when the client sends a request to

the lower tier data center if the

content is not cached the upper tier

data center is checked this time however

if the content is not cached at the

upper tier the upper tier checks cash

Reserve instead of requesting straight

from the origin

if the content is not present in cash

Reserve cash Reserve will request it

from the origin once response is

returned from the origin cash Reserve

caches the content while replying to the

upper tier which also caches it and

Returns the response to the lower tier

which also caches it and responds to the

client now next time the same content is

requested if there is a cache Miss at

the lower tier data center the upper

tier data center is checked now if

there's say cache missed at the upper

tier data center let's say expired TTL

or content has been evicted cash Reserve

will be checked and if content exists at

Cash reserve it will be returned and

cached at the upper tier before being

returned and cashed at the lower tier

and returned to the client so you can

see here how cash Reserve acts as the

ultimate upper tier and minimizes the

need to pull from the origin decreasing

unnecessary egress fees

with that let's jump into the demo for

demonstration purposes I deployed a site

here that's basically a large image and

video gallery for uploading and

downloading content

now again for demonstration purposes the

website is actually hosted on a

third-party Cloud I also have automated

traffic running to simulate visitors

accessing the site

so now I'm going to go over and head

over to my cloudflare dashboard and here

you can see I have cash Reserve enabled

and it shows the current amount of data

stored in cash Reserve as well as the

total aggregate storage used over the

specific time period and you also have a

view of total cash Reserve read and

write operations once enabled cash

Reserve will start caching files with a

retention period of 30 days which will

be reset on any hits

customers can also pause using cash

Reserve meaning cloudflare's network

will no longer use cash Reserve to serve

data

here under overview you can see the

overall cash status including content

served by cloudflare and content served

by the origin

you can see the vast majority of

requests are served by cloudflare and if

you scroll down here and hover over the

cast status you can see a

92.96 cash hit ratio really good now

since I just enabled cash reserve a few

days ago if I go up here instead of 24

hours I select previous 30 days

we could see the cash hit ratio was

lower at around 80 percent so cash

Reserve really helped get into that 90

plus ratio getting us closer and closer

to that hundred percent

and scrolling down here you can see more

overall caching details in general like

the most popular content types and what

specific content is the most popular

here on the left you can also Purge the

cache which will also Purge content and

cash reserves you can also create page

rules to get more granular on any

specific caching behavior let's go into

this and take a look in more detail you

can see I created a page rule matching

on all requests that contain this

specific domain name

and I set the cache level to Cache

everything that's cachable but also can

select different cash level including

bypassing cache if desired

so now I'm gonna head over to caching

and look at Cash rules

so under cash rules I can also create a

rule as I did here to override ttls from

Cache control headers

this is done right at the edge and you

can see here if I click into it

all requests to this hostname

I've configured as content eligible for

caching and overridden the origin TTL

setting it to 12 hours with cloudflare

httl it makes it very convenient to set

TTL in one place for all assets

now I'm going to head over to analytics

and logs there

and I'll go under logs you can see I've

set up a log push I'm just going to

click edit here

last thing I want to show here is you

can also log data to external logs and

include the cash Reserve used field to

get more visibility into requests and

respective content being served from

cash Reserve I hope you found this

cloudflare cash Reserve walkthrough in

demo informational and useful for

additional details make sure to check

out the cloudflare cash Reserve product

page