Amazon S3 gaurantees that the data being uploaded to bucket will be spread across >= 3 AZs.scroll down for chart. When we create bucket, we enter region. How amazon manages this AZs number when we create bucket in the region where we have only two AZs?
here's the answer from AWS S3 FAQ. Apparently, in those cases, more AZs exist, but they are not publicly available:
Q: What is an AWS Availability Zone (AZ)?
An AWS Availability Zone is an isolated location within an AWS Region. Within each AWS Region, S3 operates in a minimum of three AZs, each separated by miles to protect against local events like fires, floods, etc.
Amazon S3 Standard, S3 Standard-Infrequent Access, and S3 Glacier storage classes replicate data across a minimum of three AZs to protect against the loss of one entire AZ. This remains true in Regions where fewer than three AZs are publicly available. Objects stored in these storage classes are available for access from all of the AZs in an AWS Region.
The Amazon S3 One Zone-IA storage class replicates data within a single AZ. Data stored in this storage class is susceptible to loss in an AZ destruction event.
Related
This https://aws.amazon.com/blogs/storage/architecting-for-high-availability-on-amazon-s3/#:~:text=Amazon%20S3%20maintains%20redundancy%20even%20within%20one%20of,can%20still%20access%20their%20data%20with%20no%20downtime states the following:
Amazon S3 storage classes replicate their data on more than three
Availability Zone (except for S3 One Zone-Infrequent Access).
What's the point of this article https://aws.amazon.com/blogs/startups/large-scale-disaster-recovery-using-aws-regions/ stating:
S3 snapshots: We rely on the cross s3 sync and this works like a
charm. We are able to copy the data from our primary to the DR region
within a matter of few minutes.
The latter seem superfluous now and is from 2017, so may be it is out-dated? Or is it the thrust that we should also be be placing Amazon S3 copies over over Regions? I see no such need as the AZ's within a Region are physically separated from each other. What am I missing?
S3 buckets are region specific. When you create a new bucket you need to select the target region for that bucket.
For DR reasons, you can keep backups in another region. Should the primary region fail in a way that the entire region is affected, then you could restore in the backup region.
Your DR strategy will depend on your use case, and your needs for returning services back to normal in case of region wide failure.
For example, let's say you rely on ec2/ebs to operate your service and those services suffer region wide outage for 5 hours. In order to recover your service you would need to move to a region where the resources are available. Assuming you need S3 data for operational processing you would want to have that data ready in the Target recovery region.
Storing in multiple AZs in a region does not guarantee safety in case of entire region failure.This is applicable for all regional services. The article you shared indeed mentions this so it is not irrelevant.
The service that runs in HA is handled by hosts running in different
availability zones but in the same geographical region. This approach,
however, does not guarantee that our business will be up and running
in case the entire region goes down
Amazon announced on April 2018 the availability of a new storage class, named One-Zone Infrequent Access, that complements the plain IA option by lowering the cost via the usage of only one AZ for storage.
Its site, advertises that all storage classes have the so-called 11 9s durability.
My question is how two options (IA vs One Zone IA) can have the same (i.e. 11 9s) durability, given that the later uses 1 AZ (vs multiple of the former)
Amazon S3 Standard, S3 Standard-IA, S3 One Zone-IA, and Amazon
Glacier, are all designed for 99.999999999% durability. Amazon S3
Standard, S3 Standard-IA and Amazon Glacier distribute data across a
minimum of three geographically-separated Availability Zones to offer
the highest level of resilience to AZ loss. S3 One Zone-IA saves cost
by storing infrequently accessed data with lower resilience in a
single Availability Zone. Amazon S3 Standard-IA is a good choice for
long-term storage of master data that is infrequently accessed. For
other infrequently accessed data, such as duplicates of backups or
data summaries that can be regenerated, S3 One Zone-IA provides a
lower price point
ps. I think they are themselves implying that one zone has lower durability.
One Zone-IA saves cost by storing infrequently accessed data with lower resilience in a single Availability Zone
S3 One Zone IA is just as durable from an engineering standpoint as the other storage classes except in the event that the availability zone where your data is stored is destroyed.
S3 One Zone-IA offers the same high durability†, high throughput, and low latency of Amazon S3 Standard and S3 Standard-IA
...
† Because S3 One Zone-IA stores data in a single AWS Availability Zone, data stored in this storage class will be lost in the event of Availability Zone destruction.
https://aws.amazon.com/s3/storage-classes/
So, the claim being made appears to be that 1ZIA is using the same engineering design as other storage classes -- redundant storage media -- except that everything is physically in a single AZ rather than distributed across multiple zones... so it offers comparable durability... except for the case of a catastrophic event involving that AZ.
It seems that having one AZ instead of 2, does reduce the availability:
Amazon S3 One Zone-Infrequent Access (S3 One Zone-IA)
Same low latency and high throughput performance of S3 Standard
Designed for durability of 99.999999999% of objects in a single
Availability Zone†
Designed for 99.5% availability over a given year
Backed with the Amazon S3 Service Level Agreement for availability
Supports SSL for data in transit and encryption of data at rest S3
Lifecycle management for automatic migration of objects to other S3
Storage Classes
I use AWS and have automatic backup enabled.
For one of our client, we need to know exactly where the backup data is stored.
From the AWS FAQ website, I can see that:
Q: Where are my automated backups and DB Snapshots stored and how do I manage their retention?
Amazon RDS DB snapshots and automated backups are stored in S3.
My understanding is that you can have a S3 instance located anywhere you want, so it's not clear to me where this data is.
Just to be clear, I'm interested by the physical location (is it Europe, US....)
It is stored in the same AWS region where the RDS instance is located.
When you directly store data in S3, you store it in an S3 container called a bucket (S3 doesn't use the term "instance") in the AWS region you choose, and the data always remains only in that region.
RDS snapshots and backups are not something you store directly -- RDS stores it for you, on your behalf -- so there is no option to select the bucket or region: it is always stored in an S3 bucket in the same AWS region where the RDS instance is located. This can't be modified.
The data from RDS backups and snapshots is not visible to you from the S3 console, because it is not stored in one of your S3 buckets -- it is stored in a bucket owned and controlled by the RDS service within the region.
According to this :
Your Amazon RDS backup storage for each region is composed of the automated backups and manual DB snapshots for that region. Your backup storage is equivalent to the sum of the database storage for all instances in that region
I think that means that it is stored in that region only and s3 stores data like this :
Amazon S3 redundantly stores data in multiple facilities and on multiple devices within each facility. To increase durability, Amazon S3 synchronously stores your data across multiple facilities before confirming that the data has been successfully stored.
https://aws.amazon.com/rds/details/backup/
...By default, Amazon RDS creates and saves automated backups of your DB instance securely in Amazon S3 for a user-specified retention period.
...Database snapshots are user-initiated backups of your instance stored in Amazon S3 that are kept until you explicitly delete them
I have created an S3 Bucket and mounted into one of my EC2 servers in the same region. Then I put data into the bucket using FTP account created for that EC2 instance. Finally, I access the data by Http request.
I'm not accessing S3 bucket directly from Internet, either for writing or accessing. All the data transferred through EC2 instance.
So, I assume per month charges as below, for fully used up 1TB S3 bucket (standard storage),
Storage Pricing - $0.0300*1024 = $30.72
Request Pricing - $0.005*10 = $0.05 (Assumed 10,000 request per month )
Data Transfer Pricing - Nill (Since the bucket is not being accessed directly)
Is that correct? or data transfer pricing is applicable?
Ref: Pricing Details
You do not pay for data transfer between S3 and EC2 in the same region, however you pay for Data Transfer OUT From Amazon EC2 To Internet or EC2 instance in a different availability zone in the same region.
See EC2 pricing for more details.
If you transfer 1TB of data OUT to Internet from AWS, either directly from S3 or through EC2 instance, you will pay the same price.
TIP:
If you are transferring big amount of data from S3 out to Internet, look into CloudFront. Data transfer EC2/S3/ELB -> CloudFront is free of charge and CloudFront has cheaper rates per Gb compared to downloading files directly from S3.
EDIT:
see #Michael - sqlbot's comment, this is often but not always true depending on S3 Bucket's region and CloudFront edge location serving the content.
TIP 2:
For really large amounts of data it might be worth setting up DirectConnect connection (private connection from your office / on-premise setup to AWS). Then Data Transfer becomes even cheaper per Gb, however you start paying hourly rate for your DirectConnect link. Do the math to calculate what's best for you.
If you are reading data from S3 to your EC2 instance, and the S3 bucket is in the same region as your EC2 instance, then there are no data transfer costs.
Broken down:
There is no “data transfer in” costs to your EC2 instance if the data is coming from an S3 bucket in the same region: EC2 Instance Pricing – Amazon Web Services (AWS)
There is no “data transfer out” costs from your S3 bucket if the data is going to an EC2 instance in the same region: Cloud Storage Pricing – Amazon Simple Storage Service (S3) – AWS
There is no "data tansfer out" costs from EC2 to S3.
More info:
https://www.quora.com/In-AWS-EC2-what-counts-towards-data-transfer-costs
I am confusing about the Amazon S3 replica mechanism. In my understanding, by default, Amazon S3 applies 3-replica mechanism, in which there will be 3 replicas for each object created on my S3 bucket. And all the replicas are stored in multiple availability zones within only ONE region, which I specified when creating S3 bucket.
Is my understanding correct? If it's correct, is it possible to see where the replicas of an object are stored?
Thanks
You are pretty much correct. S3 replication works by replicating across at least 3 data centers, over at least two AZs within a single region (each availability zone can have multiple data centers).
The replication is part of s3, which is a managed service, meaning you just have to accept what they're telling you. Telling you where the replicas were wouldn't really serve any purpose, and AWS never really disclose the details of their infrastructure to anyone who doesn't need to know. Even if they told you the data was stored in Availability Zone 1 and 2, this is effectively meaningless information, as zones are aliases, i.e your Zone 1 probably isn't the same as my Zone 1.