Migrating Dynamodb Data between regions - amazon-web-services

I've a requirement to copy and move (depend on the case) items between AWS Dyanmodb regions.
For example, let's say, there is a USER table in ap-south-1 region and I want to move some items of it to the us-east-1 region.
So is there any way to migrate the data from one region to another considering large data set in mind?
I've read this solution [https://tvernon.tech/blog/move-dynamodb-data-between-regions]. But I am not sure how feasible it would be with large dataset.
See, I am not talking about Global tables here, which gives multi-region replication as a feature.

Related

Calculating time required for DynamoDB global table to replicate to a new region

I have a DynamoDB Global table already setup in us-west-2 and eu-west-1 regions. I want to add a new replica to us-east-1 region and want to calculate how much time will it take for the new replica in us-east-1 to have all the items from other regions. How to calculate the total time required for replication?
The way to do this is to restore from backup to a new table and test adding a region with global tables. I can tell you that each partition gets a worker and all replication is done in parallel. So it will be as fast as it can possibly be over the DynamoDB backplane.

Can I stop the replicas of a DynamoDB global table from synchronising?

I am having DynamoDB table in a specific region but the data it contains support application instances in multiple regions. I want to create a DDB per region setup without downtime.
In the end I want to have multiple instances running, each one in it's own region with it's own regional database table, but I also want the two tables to be in sync while the migration is rolling out.
I know that I can use DynamoDB streams with lambda to keep the two tables in sync for as long as I need, but I wonder if there's an easier way.
The idea is to add the extra region to the existing table, making it a global table. This will allow each local instance to use it's local database while also keeping the data in sync among regions.
But I don't want to maintain a global table for ever since after the migration is completed there's no reason to keep the replicas in sync.
So, is it possible to stop the replicas of a global table from syncing?
Is is possible to split a global table to it's local parts?
I couldn't find anything in the docs, but maybe I missed something.

DynamoDB Global Table Backup & Restore

I have a global DynamoDB table that is currently replicated across 3 regions (eu-west-1, eu-west-2, eu-central-1).
As part of a PoC piece of work I am looking to use AWS Backup to schedule automated backups, I was wondering what the best practice for this was?
Is it acceptable to take backups of a single region, i.e only schedule the backups for the table in eu-west-1? Then when it comes to recovering the table, I can go through the process of first restoring to a non-global table, then adding replica's.
Or is it better practice to ensure all region's tables are backed up at the same time?
I would suggest that you backup from a single region (perhaps if you have a primary region for writes use this.
If you restore the DynamoDB table, it needs to create a new DynamoDB table resource. Once this is restored you would then add your global tables which would replicate the data currently stored in the restored DynamoDB table.
By having multiple backups, you would need to have a strategy to preprocess for any differences between all regions your table exists.

Amazon DynamoDB - geographically distributed?

I am new to AWS. Sorry if my question is basic, got stuck with this term.
AWS Global Infrastructure says "18 geographic Regions" -> Geographic term is used along with Regions, that makes sense.
DynamoDB FAQs 3rd questions says, "Amazon DynamoDB stores three geographically distributed replicas of each table to enable high availability and data durability."
Here(three geographically) is it referring to Region or Availability Zones ? Bit confused. If it is Region, does it mean my data is going out of my country(if my country has only 1 Region).
Please suggest.
Geographically isolated in this documentation refers to Availability Zones and not Regions. As per AWS documentation when you create a table in one region, it's replicated in others zones to ensure the high availability. If you do some activity in the table it's updated in the replicas. The AZ's are interconnected with low latency networks.
The data is stored on SSD disks and automatically replicated across
multiple Availability Zones in an AWS region, which brings the high
availability and your data is durable.
If you create a table in one region, the same table can be created in other regions also with same name.
If you want your table to be replicated in other regions you must enable the Cross-Region replication. For more details Refer
DynamoDB
All Things about DynamoDB
Almost every AWS service revolves around two things in availability: Multi AZ (multiple data centers in a single region) and Cross-Region (different geographic locations across globe) and so does the DynamoDB. By default AWS DynamoDB is a multi-AZ enabled service which means that your data is by default replicated across 3 data centers (minimum of 2 AZs) but for cross-region, you need to enable DynamoDB global tables (DynamoDB Streams).
Multi-Region Replication with DynamoDB
DynamoDB global tables are geographically distributed. They provide a fully managed solution for deploying a multiregion, multi-active database. Like with every other geographically distributed database, GlobalTables comes with ReplicationLatency.
An important thing to note here is, DynamoDB does not offer cross-region strong consistency (this is in contrast with CosmosDB, a similar offering from Azure)
From AWS documentation:
An application can read and write data to any replica table. If your
application only uses eventually consistent reads and only issues
reads against one AWS Region, it will work without any modification.
However, if your application requires strongly consistent reads, it
must perform all of its strongly consistent reads and writes in the
same Region. DynamoDB does not support strongly consistent reads
across Regions. Therefore, if you write to one Region and read from
another Region, the read response might include stale data that
doesn't reflect the results of recently completed writes in the other
Region.
Also, global tables are not to be confused with global indexes. Global indexes get their name because they are used in fetching data across multiple DynamoDB partitions.
"Amazon DynamoDB stores three geographically distributed replicas of each table to enable high availability and data durability."
This is specifically referring to multi AZ structure of dynamo, this helps in achieving high availability of your table. eg. if one of availability zone is down you still will be able to access you table.
To answer "my data is going out of my country(if my country has only
1 Region)."
For multi region its not by default ON you need to use global tables and specify regions in which you want to replicate that means your data/table wont go in any other region till you specifically want it to be.
For more on global tables refer
https://aws.amazon.com/dynamodb/global-tables/

DynamoDB Table Missing?

I had created a simple table in dynamo called userId, I could view it in the AWS console and query it through some java on my local machine. This morning, however, I could no longer see the table in the dynamo dashboard but I could still query it through the java. The dashboard showed no tables at all (I only had one, the missing 'userId'). I then just created a new table using the dashboard, called it userId and populated it. However, now when I run my java to query it, the code is returning the items from the missing 'userId' table, not this new one! Any ideas what is going on?
Ok, that's strange. I thought dynamo tables were not specified by region but I noticed once I created this new version of 'userId' it was viewable under the eu-west region but then I could see the different (previously missing!) 'userId' table in the us-east region. They both had the same table name but contained different items. I didn't think this was possible?
Most of the services of Amazon Web Services are in a single region. The only exceptions are Route 53 (DNS), IAM, and CloudFront (CDN). The reason is that you want to control the location of your data, mainly for regulatory reasons. Many times your data can't leave the US or Europe or any other region.
It is possible to create high availability for your services within a single region with availability zones. This is how the highly available services as DynamoDB or S3 are giving such functionality, by replicating the data between availability zones, but within a single region.