What is S3

1) What is S3

Highly-scalable, reliable, and low-latency data storage infrastructure at very low costs.

Can be used to store and retrieve any amount of data, at any time, from within Amazon EC2 or from anywhere on the web

2) Types of S3 Storage and its Durablity/Availablity

S3 has four following storgae Classes, where Glacier is used to archive objects for long term. Different storage class has different pricing.

a) S3 Standard

b) S3 Standard – Infrequent acces

c) Glacier

d) S3 – RRS (Reduced Redundancy Storage)

Durablity -  11 9’s - STD, STD-IA and Glacier &  4 9’s - RRS

Availablity – 4 9’s - STD, RRS  &  3 9's -  STD-IA 

RRS - Storage option that enables customer to reduce their costs for storing non-critical data. Annual expected loss 0.01 %

3) Bucket URL format 

http://<bucketname>.s3.amazonaws.com/<objectpath>

4) About S3 Object

Each S3 object has Data, key and metadata

a) Key  - An unique identifier for an object with bucket. Key is object name. Every object has only one key.

b) Metadata is set of name - value pairs. You can set object metadata the time you upload it. After you upload you cannot modify the object metadata. the only way to modify is make a copy of the object ans set the metadata. the data about the data and is a set of name-value pairs that describe the object for e.g. con tent-type, size, last modified. Custom metadata can also be specified at the time the object is stored.

Version ID is the version id for the object and in combination with the key helps to unique identify an object within a bucket

Subresources helps provide additional information for an object

Access Control Information helps control access to the objects

5) Limits

(i)  Bucket - 100/Account  (If need more request can be raised to AWS)

(ii) File Size - 0 to 5 TB

6) Consistency

a) New objects - Read after Write consistency for all regions

b) Overwrite PUTs and DELETE's - Eventual consistency for overwrite 

7) Requestor Pays

S3 billing happens based on the amount of data stored. And o minimum billing. Amount of data out from the bucket and amount requests received for a object. (Like Reading Object, Listing Object., put get, delete)

If Request pays is enabled the cross acccount owner will pay data out charge and request chrge. But still storage charge will be paid by bucket owner.

Transfer accelartion : let say from banagleotr we want upload some data from blr to tokyo. normally it will go by pubic network. If this enabled searches for one of the nearest edge location (eg blr to chennai public network from there it uses amazon netowrk)

Notes:

a) If there is no Edit in the file in S3 and if you upload another file of same name, it is overwritten if versioning is not enabled. A new version is created if version is maintained.

b) Within the Region data is replicated into multiple availablity zone's.

c) Ownership of the object is not transferable.

d) Version ID is the version id for the object and in combination with the key helps to unique

c) Identify an object within a bucket

e) Subresources helps provide additional information for an object

f) Access Control Information helps control access to the objects