‫The first kind of databases we're gonna see
‫is the relational databases and for it we have RDS.
‫RDS stands for Relational Database Service,
‫so it's very clear that it's only for
‫relational databases, and we'll be using the SQL language.
‫So it's a managed database service
‫for databases that will use SQL as a query language
‫and it will allow you to create databases in the cloud
‫that will be managed by AWS.
‫These databases can be of different kinds.
‫It could be a Postgres, MySQL, MariaDB, Oracle,
‫Microsoft SQL Server, and finally something called Aurora,
‫which is a proprietary database from AWS
‫which we'll be seeing in this lecture as well.
‫So, why would we use RDS
‫instead of deploying our own database on EC2?
‫Well, RDS is a managed database service.
‫So, provisioning the database will be automatic.
‫The patching of the operating system
‫will be done by AWS.
‫We will have continuous backups and restore options
‫with point in time restore.
‫We'll have monitoring dashboards,
‫to see if our database is doing good.
‫We'll be able to scale the reads by creating a read replicas
‫and improve the read performance.
‫We will have the way to set up multi AZ to make sure
‫that we're ready to have a plan for disaster recovery
‫against an whole availabilities on going down.
‫And, finally, we can set up maintenance windows
‫for upgrades and we can scale vertically
‫and horizontally.
‫This storage is going to be backed by EBS,
‫would it be a gb2 type or io1 type volume,
‫and the only thing that we cannot do
‫with an RDS database is that we cannot SSH
‫into your RDS database instance.
‫Okay, we're just using the service
‫AWS manage the entirely the database for us
‫so we cannot use the SSH utility to see
‫what's going on within our database.
‫Okay, so where does RDS fit
‫within our solution architecture?
‫Well, we have a load balancer
‫and it's fronting multiple backend EC2 instances.
‫They are possibly into an auto scaling group.
‫And they need to store and share the data somewhere
‫and this is structured data so they're not going
‫to use EBS or EFS or EC2 instance store.
‫They will be using a database
‫and in this example,
‫it is a relational database, so SQL-based.
‫And the EC2 instances will be connecting to database
‫and doing read/writes and all at once.
‫So they will be sharing the database in the backend.
‫And this is a classic solution architecture
‫not just using RDS but using any kind of database.
‫You have the load balancer layer
‫that will be taking the web request,
‫the backend EC2 instances doing the application logic
‫and the last tier which is (mumbles)
‫which is the database here doing the reads
‫and the writes of the data.
‫Okay, so this is for the RDS.
‫So now for the Aurora,
‫so Aurora is going to be
‫a database technology created by AWS.
‫It's not open sourced.
‫And it works the same way as RDS,
‫we have our EC2 instances connecting directly
‫into Amazon Aurora
‫and Aurora supports two kinds of database technologies.
‫It supports PostgreSQL and MySQL.
‫The idea with Aurora is that
‫it's going to be cloud optimized
‫and so there is a 5x performance improvement
‫over MySQL on RDS
‫and a 3x improvement over using Postgres on RDS.
‫On top of things, we don't need to worry
‫about the storage of an Aurora database
‫because the storage will grow automatically
‫in increments of 10GB, up to 128TB.
‫Even if Aurora is going to be more expensive than RDS,
‫about 20% more, it's going to be more efficient
‫and so it should be more cost effective.
‫Finally, Aurora is not something that's included
‫into the free tier of AWS but RDS is, okay?
‫So from an exam perspective,
‫RDS and Aurora are going to be the two ways
‫for you to create relational databases on AWS.
‫They're both managed
‫and Aurora is going to be more cloud native
‫whereas the RDS is going to be running the technologies,
‫you know, directly as a managed service.
‫Now, will see you in the next lecture just to give it a go
‫and try to create our first database.