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.
Under terms of the agreement, Akamai has agreed to acquire all of the outstanding equity of Linode Limited Liability Company for approximately $900 million, after customary purchase price adjustments. As a result of structuring the transaction as an asset purchase, Akamai expects to achieve cash income tax savings over the next 15 years that have an estimated net present value of approximately $120 million. The transaction is expected to close in the first quarter of 2022 and is subject to customary closing conditions.
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.
