S3 Flashcards
Lear all about S3
What is S3?
“Simple Storage Service”. It is essentially a key-value store.
It provides secure, durable, highly-scalable object storage with a simple web interface to store and retrieve any amount of data from anywhere on the web.
What is the size limitation on S3?
Files can be 0 bytes to 5 TB. There is unlimited storage (pay by the GB).
What are buckets?
That is where files are stored. Think of them as folders.
The bucket namespace is universal. It must be unique globally.
What do the S3 Bucket URLs look like?
“https://s3-region.amazonaws.com/bucketname”, e.g., “https://s3-eu-west-1.amazonaws.com/my-bucket”
What is the data consistency model for S3?
- Read after write consistency for PUTS of new object.
* Eventual consistency for overwrite PUTS and DELETES (can take time to propagate)
What does the store look like?
- Key: this is the object name
- Value: this is the object value
- Version ID: used for versioning
- Metadata: data about what is being stored
- Subresources:
- Access Control Lists
- Torrents
What is the availability, durability of S3?
Built for 99.99%, Amazon guarantees 99.9% availability.
Amazon guarantees 99.999999999% durability (11 nines).
What are the storage tiers/classes?
- S3 Standard: 99.99% availability, 99.999999999% durability. Stored redundantly across multiple devices in multiple facilities and is designed to sustain the concurrent loss of 2 facilities.
- S3 - IA: Infrequently access. For when data is accessed less frequently but requires rapid access when needed. Lower fee than S3 standard but incurs a retrieval fee.
- S3 One Zone - IA: lower cost than IA and does not require multiple availability zone (stored in 1 availability zone only) resilience.
- Glacier: very cheap for archival use only. Comes in 3 flavors: expedited, standard, and bulk. An expedited retrieval takes a few minutes (more expensive). A standard retrieval takes 3-5 hours. Bulk takes 5-12 hours.
What S3 charges are there?
- Storage (e.g, charged per GB)
- Requests (e.g., 1000 requests/minute)
- Storage manage pricing (e.g, tags/metadata)
- Data transfer pricing (e.g., transfering from one region to another, i.e., cross region replication)
- Transfer acceleration (e.g, takes advantage of CloudFront’s technology )
Have you read the S3 FAQ?
No!. READ IT before exam.
Are objects public or private by default?
Objects are not public by default. All buckets are also private by default.
What are the types of server side encryption?
- Server side encryption with Amazon S3 managed keys (SSE-S3)
- Server side encryption with KMS (SSE-KMS)
- Server side encryption with customer provided keys (SSE-C)
If an versioning is turned on and an object is made public and then a new version is uploaded, is the new version public?
What about if the new version is then deleted, is the previous version still public?
The new version will not be public but once it is deleted the previous version will still be public since it was made public before (and S3 remembers).
Can you add 2-FA/MFA for deleting an object?
Yes. (only if versioning is enabled?)
When you set up new S3 replication, which object get replicated?
New objects and changed objects. Existing objects will not get replicated. If you want to move existing files over then you must use the command line tool.
