Mountpoint for Amazon S3 is optimized for read-heavy workloads that need high throughput. It intentionally does not implement the full POSIX specification for file systems.
In particular, you can specify the use of any one of four widely used checksum algorithms (SHA-1, SHA-256, CRC-32, and CRC-32C) when you upload each of your objects to S3.
^gt; The service will be called R2 — “one less than S3,” quipped Cloudflare CEO Matthew Prince in an interview with Protocol ahead of Cloudflare’s announcement
Oh I never thought of that. So the next one is Q1 and final one would be P0.
R2 builds on Cloudflare’s commitment to the Bandwidth Alliance, providing zero-cost egress for stored objects — no matter your request rate. Egress bandwidth is often the largest charge for developers utilizing object storage and is also the hardest charge to predict. Eliminating it is a huge win for open-access to data stored in the cloud.
That doesn’t mean we are shifting bandwidth costs elsewhere. Cloudflare R2 will be priced at $0.015 per GB of data stored per month — significantly cheaper than major incumbent providers.
在 durability 的部份，與 S3 都是一年 11 個 9：
The core of what makes Object Storage great is reliability — we designed R2 for data durability and resilience at its core. R2 will provide 99.999999999% (eleven 9’s) of annual durability, which describes the likelihood of data loss.
目前還沒有公開，算是先對市場放話：
R2 is currently under development — you can sign up here to join the waitlist for access.
Per-object metadata is stored within a discrete S3 subsystem. This system is on the data path for GET, PUT, and DELETE requests, and is responsible for handling LIST and HEAD requests. At the core of this system is a persistence tier that stores metadata. Our persistence tier uses a caching technology that is designed to be highly resilient. S3 requests should still succeed even if infrastructure supporting the cache becomes impaired. This meant that, on rare occasions, writes might flow through one part of cache infrastructure while reads end up querying another. This was the primary source of S3’s eventual consistency.
如果要解決 Eventually Consistent，最直接的想法是拔掉 cache，但這樣對效能的影響太大，所以得在要保留 cache 的情況下設計，所以就想到用其他管道確保 cache 裡的資料狀態是正確的：
One early consideration for delivering strong consistency was to bypass our caching infrastructure and send requests directly to the persistence layer. But this wouldn’t meet our bar for no tradeoffs on performance. We needed to keep the cache. To keep values properly synchronized across cores, CPUs implement cache coherence protocols. And that’s what we needed here: a cache coherence protocol for our metadata caches that allowed strong consistency for all requests.
We had introduced new replication logic into our persistence tier that acts as a building block for our at-least-once event notification delivery system and our Replication Time Control feature. This new replication logic allows us to reason about the “order of operations” per-object in S3. This is the core piece of our cache coherency protocol.
These verification techniques were a lot of work. They were more work, in fact, than the actual implementation itself. But we put this rigor into the design and implementation of S3’s strong consistency because that is what our customers need.
Previously, to copy AMIs across these AWS regions, you had to rebuild the AMI in each of them. These partitions enabled data isolation but often made this copy process complex, time-consuming and expensive.
This feature provides a packaged format that allows AMIs of size 1TB or less to be stored in AWS Simple Storage Service (S3) and later moved to any other region.
然後目前只有透過 cli 操作的方式，或是直接用 SDK 呼叫 API，看起來 web console 還沒提供：
This functionality is available through the AWS Command Line Interface (AWS CLI) and the AWS Software Development Kit (AWS SDK). To learn more about copying AMIs across these partitions, please refer to the documentation.
Effective immediately, all S3 GET, PUT, and LIST operations, as well as operations that change object tags, ACLs, or metadata, are now strongly consistent. What you write is what you will read, and the results of a LIST will be an accurate reflection of what’s in the bucket. This applies to all existing and new S3 objects, works in all regions, and is available to you at no extra charge! There’s no impact on performance, you can update an object hundreds of times per second if you’d like, and there are no global dependencies.
要注意這邊沒有提到 DELETE，所以有可能 DELETE + GET 的操作還是沒有到 strong consistency，不過句子本身意思不是很清晰，也許這幾天會有人在 forum 上面問然後有答案...
We’ve been working with the Amazon EMR team and developers in the open-source community to ensure that customers can take advantage of this update with their big data workloads. As a result of that you no longer need to use EMRFS Consistent View or S3Guard, further reducing the cost to run big data workloads in AWS.
