We do eviction based on an algorithm called “least recently used” or LRU. This means that the least-requested content can be evicted from cache first to make space for more popular content when storage space is full.
The Cache Reserve Plan will mimic the low cost of R2. Storage will be $0.015 per GB per month and operations will be $0.36 per million reads, and $4.50 per million writes.
另外還有還沒公告的 Cache Reserve 的部份：
(Cache Reserve pricing page will be out soon)
對於很極致想要拼 hit rate 的使用者來說是個選擇就是了，另外可以想到直播相關的協定 (像是 HLS) 好像可以這樣搞來壓低對 origin server 的壓力？
The PSL contains multi-party domain suffixes and is used by a wide range of client software (for example, web browsers) to implement policy decisions, such as to prevent cookies from being set on public or multi-party domains.
以往會自己去「AWS IP address ranges」這邊提供的 JSON 檔案定時撈出來再丟到 managed prefix list 裡面，這次的功能等於是 AWS 自己管理這個 prefix list 讓管理者使用。
馬上想的到的用途就是 HTTP/HTTPS port 了，只開放給 CloudFront 的伺服器存取：
Starting today, you can use the AWS managed prefix list for Amazon CloudFront to limit the inbound HTTP/HTTPS traffic to your origins from only the IP addresses that belong to CloudFront’s origin-facing servers. CloudFront keeps the managed prefix list up-to-date with the IP addresses of CloudFront’s origin-facing servers, so you no longer have to maintain a prefix list yourself.
要注意的是這不應該當作唯一的 ACL 手段，因為其他人也可以建立 CloudFront distribution 來穿透打進你的 origin server。
另外有個比較特別的地方，這個 prefix list 的權重很重，使用他會算 55 條 rule 的量，在 security group 內很容易撞到 60 條的限制，在 route table 裡面則是直接撞到 50 條的限制；不過這兩個限制都可以跟 AWS 申請調昇：
The Amazon CloudFront managed prefix list weight is unique in how it affects Amazon VPC quotas:
It counts as 55 rules in a security group. The default quota is 60 rules, leaving room for only 5 additional rules in a security group. You can request a quota increase for this quota.
It counts as 55 routes in a route table. The default quota is 50 routes, so you must request a quota increase before you can add the prefix list to a route table.
單 CPU 的伺服器是四個 100Gbps 界面接出來，雙 CPU 的伺服器是八個 (這邊 SUT 是 system under test 的縮寫)：
These client systems were connected to the CDN servers using 100 GbE links through a switch; 4x100 GbE connections for the single-processor SUT, and 8x100 GbE for the dualprocessor SUT. Testing was done using Wrk, a widely recognized open-source HTTP(S) benchmarking tool.
在白皮書最後面也有提到測試的配置，都是在 Ubuntu 20.04 上面跑，單 CPU 用的是兩張 Intel 的 100Gbps 網卡，雙 CPU 的用的是四張 Mellanox 的 100Gbps 網卡：
3rd generation Intel Xeon Scalable testing done by Intel in September 2021. Single processor SUT configuration was based on the Supermicro SMC 110P-WTR-TNR single socket server based on Intel® Xeon® Platinum 8380 processor (microcode: 0xd000280) with 40 cores operating at 2.3 GHz. The server featured 256 GB of RAM. Intel® Hyper-Threading Technology was enabled, as was Intel® Turbo Boost Technology 2.0. Platform controller hub was the Intel C620. NUMA balancing was enabled. BIOS version was 1.1. Network connectivity was provided by two 100 GbE Intel® Ethernet Network Adapters E810. 1.2 TB of boot storage was available via an Intel SSD. Application storage totaled 3.84TB per drive and was provided by 8 Intel P5510 SSDs. The operating system was Ubuntu Linux release 20.04 LTS with kernel 5.4.0-80 generic. Compiler GCC was version 9.3.0. The workload was wrk/master (April 17, 2019), and the version of Varnish was varnishplus-6.0.8r3. Openssl v1.1.1h was also used. All traffic from clients to SUT was encrypted via TLS.
3rd generation Intel Xeon Scalable testing done by Intel in September 2021. Dual processor SUT configuration was based on the Supermicro SMC 22OU-TNR dual socket server based on Intel® Xeon® Platinum 8380 processor (microcode: 0xd000280) with 40 cores operating at 2.3 GHz. The server featured 256 GB of RAM. Intel® Hyper-Threading Technology was enabled, as was Intel® Turbo Boost Technology 2.0. Platform controller hub was the Intel C620. NUMA balancing was enabled. BIOS version was 1.1. Network connectivity was provided by four 100 GbE Mellanox MCX516A-CDAT adapters. 1.2 TB of boot storage was available via an Intel SSD. Application storage totaled 3.84TB per drive and was provided by 12 Intel P5510 SSDs. The operating system was Ubuntu Linux release 20.04 LTS with kernel 5.4.0-80- generic. Compiler GCC was version 9.3.0. The workload was wrk/master (April 17, 2019), and the version of Varnish was varnish-plus6.0.8r3. Openssl v1.1.1h was also used. All traffic from clients to SUT was encrypted via TLS.
一般性的 data transfer 從 1GB/month/region 變成 100GB/mo，現在是 21 regions 所以不會有反例，另外大多數的人或是團隊也就固定用一兩個 region，這個 free tier 大概可以省個 $10 到 $20 左右？
Data Transfer from AWS Regions to the Internet is now free for up to 100 GB of data per month (up from 1 GB per region). This includes Amazon EC2, Amazon S3, Elastic Load Balancing, and so forth. The expansion does not apply to the AWS GovCloud or AWS China Regions.
Data Transfer from Amazon CloudFront is now free for up to 1 TB of data per month (up from 50 GB), and is no longer limited to the first 12 months after signup. We are also raising the number of free HTTP and HTTPS requests from 2,000,000 to 10,000,000, and removing the 12 month limit on the 2,000,000 free CloudFront Function invocations per month. The expansion does not apply to data transfer from CloudFront PoPs in China.
今年十二月才生效，要注意一下不要現在就用爽爽：
This change is effective December 1, 2021 and takes effect with no effort on your part.
這樣好像可以考慮把 blog 與 wiki 都放上去玩玩看，目前這兩個服務都是用 Cloudflare 的 free tier，HiNet 用戶基本上都是連去 Cloudflare 的美西 PoP，偶而離峰時間會用亞洲的點，但都不會是台灣的 PoP...
