Hi, everyone, and welcome back.
Now, in this video, we are going to discuss about the multi asset deployment types.
Now, at a high level overview, keep a note that whenever you decide to go with multi base deployments
in ideas, there are two subtypes that are available.
First one is the multi AC instance deployment.
Second one is the multi AC cluster deployment.
Among this, the multi AC instance deployment is the older approach.
The multi AC cluster deployment is the newer approach and generally for production environment, multi
AC cluster deployment proves to be quite useful.
So let's go ahead and understand both of these.
The first approach here is the multi AC instance deployment.
Now this is also referred to as a multi AC with one standby.
So if you look into this diagram, you have the primary database instance and you have one standby that
is available.
And between both of them, there is a replication that is taking place.
Now, one thing that needs to be noted here is that this standby instance, although there is a replication
that is taking place as a user, you will not be able to perform any operation on the standby instance,
including the Reid operation.
Sometimes people wonder that anyways, the standby instance is running.
Why not use this for raid operation?
This proves to be useful because this is already added as part of your cost.
However, in this type of approach, this standby replica, there is no access at all unless and until
the primary DB fails, this standby replica becomes the new primary database.
The approach number two, as we're discussing, is the multi AC cluster deployments.
In this type of architecture, there is one writer database instance and to read the database instance
and all of them are available in three separate availability zone in the same region.
For example, here you see that you have three availability zone, right?
DB instance is available here, there are two re the database instance.
So you can also use this as a standby instance similar to what we were discussing in the approach.
Number one, the only benefit here is that not only this can act as a standby instance, you can also
perform read operation over here.
So the auto load gets distributed, right?
Operation can go to the right DB instance and read Operation can go to the reader DB instance here.
Now, when you discuss about the deployment types in IDs, there are three primary deployment types.
One is the single availability zone.
You have a multi availability zone with one standby.
So this is the approach number one, and you have the multi availability zone with two readable standby,
which is nothing but the multi AC cluster deployment.
Now when we discuss about the additional read capacity for the single availability zone, there is no
additional read capacity.
There is only one primary database instance and that database instance can be used for read and write
operation.
When we discuss about multi AC with one standby again here, there is no additional read capacity over
here since you cannot perform any read operation on the standby instance.
However, for the cluster deployments you have to stand by DB instance which are readable.
So this proves to be beneficial when we discuss about automatic failover detection for single AC.
Again, there is no and for multi AC, there will always be a failure detection in place.
When we discuss about the failover duration, this is where the cluster deployment again proves to be
useful.
So when we discuss about multi AC with one standby, you have the new primary is available to serve
the workload in as quick as 60 seconds.
However, for the cluster deployments it is much more faster, which is typically under 35 seconds.
Now before we conclude, let's go ahead and quickly look into both of these.
Now from the IDS console.
I have two database instance that are available.
One is based on the instance deployment over here.
So this is the instance deployment.
And second one is based on the cluster deployment.
Now as we're discussing in the instance deployment, all those standby replica is there, but you do
not have access to it.
So this is one thing that needs to be noted.
If I open this up, you only have endpoint and this endpoint goes to the primary database instance.
Now when we discuss about the cluster deployments, as we know that you have one right DB instance and
two reader DB instance.
So if I expand this, you see that for multi AC cluster, you have a right for instance here and you
have two reader instance.
And also one thing to note is that all of these are in separate availability zone, so writer is in
one, be reader is in one, C second reader is in one D This is one thing to note along with that,
if I quickly open this up you will see that typically the.
Two endpoints.
First endpoint is for the right, for instance.
So for the application that will be performing right operation, you'll have to supply this specific
endpoint.
And you also have one more endpoint for the reader instance.
So this is where the traffic will be directed to the set of reader DB instance in case if you want to
directly connect to a specific reader DB instance, you can also do that.
For example, if I'll open the reader DB instance, here you have its own set of endpoints as well.
All right.
So I hope with this at a high level overview, you understood the basics of the multi AC instance deployment
and the multi AC cluster deployment along with that.
Before we conclude, I also wanted to show you a few things.
So whenever you create a database with multi AC based approach.
So let's quickly look into it.
Let me just select the test.
And within a year you see that you have a multi AC db cluster and the multi ac db instance as we are
discussing, the multi ac DB cluster does come with great advantages but also with great cost.
So this is much more costly when compared to the DB instance.
So this is one thing that needs to be noted.
Apart from that, you also have certain restrictions related to the instance type and the storage that
can be used.
For example, if you select multi AC DB instance, let's go a bit down.
You have under the instance class, you have standard, you have memory optimized and you also have
more stable instance like P three micro and so on.
If I quickly select the cluster deployment over here, let's go a bit down.
You do not have the stable one that is available.
You only have the standard and the memory optimized and the same will also go for the storage.
So let's go and select the multi AC DB instance.
Let's go to the storage.
Now in the storage type, you can select the cheaper storage as well, like the general purpose SSD
along with the expensive storage like provisioning.
So this is something that can be used and even in the allocated storage, you can say 20 GB.
However, when you select the cluster option here, let's go to the storage.
You see in the storage that you do not have the general purpose, which is much more cheaper.
The only option here is the provision IOPS, SD and that to the minimum value here is 100 gigs.
All right.
So in case if you are using this, it will be a much more expensive approach in case if you are trying
it out practically as well, since you do not have the DT three micro and other instances, you will
have to go with m, fi, D and others and this will cost you quite a bit.
So this is something that needs to be noted.
Great.
So this will conclude today's video.