Is it possible to have an RDS MySQL Multi-AZ database instance that spans across two regions?
You can, but the nodes in the other regions are read replicas.
You can create one or more replicas of a given source [MySQL] DB Instance within an AWS Region or across AWS Regions and serve high-volume application read traffic from multiple copies of your data [...]
Multi-AZ Deployments and Read Replicas use different underlying replication technologies suited to their respective purposes. However, you can use them together for reliable, scalable production deployments.
Read replicas have limitations, as you might imagine. You can't write to the replicas (obviously), and there's replication lag, which might lead to data loss if the source database goes down (which is where multi-AZ helps you). The RDS FAQ has some discussion.
Related
We have an AWS Aurora database sitting on an instance that holds all of our production data. I want to be able to perform analytics on that data without doing it in our production environment, so I want to copy the production data on a daily basis to another AWS Aurora database on a completely different instance. Within that "analytics" database, I'll build out all the needed views and stored procedures to aggregate whatever transformed data I need to store.
At first I thought of creating an Aurora replica, but of course that's read-only. I need to find a way to do this outside of the production environment and I feel it's an easy enough task to do, but I just can't find out how to do it. Maybe I haven't been able to ask the write questions, so I came here. How can I achieve this?
This is simple AWS replication.
http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Aurora.Replication.CrossRegion.html
Also if you prefer to use mysql or any other RDBMS use
http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Aurora.Overview.Replication.MySQLReplication.html
It is similar to master slave replication with little difference in sharded data mainted in Aurora.
Replication is the correct (subjective, of course) solution, but you can't use a managed Aurora replica, which is to say you can't use an Aurora replica in the cluster.
That does not, however, mean you can't create your own asynchronous Aurora replica... which would be a second Aurora cluster, an independent master that is writable, but that uses the replication stream (the binary logs, also called "binlogs,") from the master cluster to keep its data in sync.
The one caveat: you must be extremely cautious not to write to any of the tables on the asynchronous cluster that are being replicated from the production master. Do that, of course, and replication breaks. The master cluster will be completely unaffected, but the replica cluster will stop replicating once inconsistent data is detected. But you can create additonal tables, views, and stored programs without issue.
Within an Aurora cluster, there is no need for replication in the traditional sense -- the replicas use the same backing store as the master (the "cluster volume.") Here, we're just replicating from cluster to cluster, identical to the way two ordinary MySQL servers would replicate (in one direction, only, of course).
The setup is essentially identical to the setup for replicating in and out of Aurora, to or from MySQL. Since this solution uses MySQL native replication, the steps are the same.
http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Aurora.Overview.Replication.MySQLReplication.html
I have a really simple bookshop webapplication written in Spring framework, just to test its scalability.
I deployed this bookshop on one EC2 instance (t1.micro), and database on Amazon RDS (t1.micro) with master/slave replication of one master instance and 3 slave instances (There's really a lot more reads than writes). One t1.micro RDS instance can have at maximum of 32 concurrent connections
Then I did stress testing with JMeter, figured out that the bottleneck is in the database, since you can have at maximum 32 concurrent connections to t1.micro RDS instance.
Should I auto scale RDS database instances, since creating new replica modifies master and it really takes long time to make it available?
Instead of using RDS should I create EC2 instances with MySQL master/replica and then auto scale these instances?
Should I shard my database instead of replication?
Application also uses com.mysql.jdbc.ReplicationDriver to load balance between master and slave instances. Should I use something different like HAProxy?
Have you ever consider Caching and Partitioning ? The web application we have worked have used Memcache. It really helps in performance issues. On the other hand If you have tables that have so much records, you should consider partitioning, accessing these tables on partitions can have remarkable affect.
I have an application database running with MySQL engine on Amazon RDS. For better availability of our data for users in all parts of the world I'm looking for the best solution.
In the previous version of the application, we mirrored our database in US and Singapore, so that users got a better performance in terms of speed and on our side, we had backup if any disaster occurred.
Now as we moved to Amazon, will having Multi A-Z Deployment serve us in the same way? I mean replicates the database in all regions but will RDS still work in a single region only?
I have done some studies but still not sure so please ask me any further questions if I'm being puzzling.
Thank you.
I think you need both the Multi-AZ and the Read Replica features of AWS RDS.
Multi-AZ just creates a non-accessible secondary DB in another availability zone and in case the primary fails, AWS would switch over to the secondary DB. So you have failover.
In the case you want to increase the performance, and your application can work in read-only mode in Singapore (for example), the Read Replica would be perfect. If writes are also required, you would need to route them to the primary read-write database.
AWS supports a combination of the two approaches.
RDS MySQL Multi-AZ deployments currently works only inside an Amazon EC2 region. RDS Read replica's also need to be present inside the same Amazon EC2 region. Inter region replication is the most requested feature in AWS RDS to replicate data to another RDS in Alternative Amazon EC2 region. It is in their road map currently.
I'm trying to understand how to architect an Amazon Web Services application.
I have an instance running off of EBS. As far as I understand, I need to mount the EBS drive so that I can store my MySQL database on it.
When I later want to scale up, how do I do so? I understand that I can add more server instances, but how will they be accessing the database? Since from what I understand, the EBS volume can only be attached to one server instance.
I can't speak to this particular setup as I do not have experience using EBS with a MySQL instance but how this type of scaling is typically accomplished is by dedicating a particular instance as the master database server. Any time you spin up additional web servers those are still using the master DB IP to connect. At the time in which your database is the bottleneck you then spin up a slave DB instance on one of the boxes (or its own dedicated box). You can then configure replication in either a master to slave direction or a circular replication so that you can write to the slave instance as well.
If you choose the classic master to slave replication then you will have to make sure your writes are only performed on the master DB instance.
You can setup something like Zeus or any other connection load balancer so that you only ever have to connect to a single Database IP which will then round-robin route your read connections to your pool of servers. Otherwise you'd have to manage the connections yourself which is definitely not trivial. Good luck.
Growing Amazon EBS Volume sizes
You can give a try to MySQL clustering on your EBS backed instances. I have similar query, with more requirements, posted here.
EBS Volumes capacity can be scaled up using Snapshot->launch new volume technique, alternatively storage capacity can be scaled out using EBS Striping (RAID 0).
In AWS you cannot mount same EBS Volume to 2 EC2 instances simultaneously, so when you are scaling your application you need to scale out / up your MySQL DB either thru Replication or clustering. AWS RDS is a very good option for MySQL , if your application is read intensive then you can scale out using RDS Read replica's as well. If you need write scaling then functional partition or MySQL Shards can be explored.
AWS has an entire product dedicated to this: RDS.
In all but the rarest and most specialized of circumstances you're going to be better off using RDS than trying to create and tune your own EBS/EC2/MySQL infrastructure.
RDS also directly answers your question - they directly enable the creation of readonly databases to use as query slaves. RDS also performs backups, upgrades, and all sorts of fail-over infrastructure for you.
With EBS there's no way to attach a disk to multiple EC2 instances, so you're not going to be able to build out a failure cluster using that approach. Instead you're going to need replication or backup tools of some type.
I am studying the new Amazon RDS product and it seems it can be scaled only vertically (i.e. put a stronger server).
Did anyone see a possibility to configure multiple instances so that one is master and the other/s is/are replication slaves?
Same question asked (and answered) here http://developer.amazonwebservices.com/connect/thread.jspa?threadID=37823
Looks like there are plans for Master-Master HA or similar but that's not the same a replicated scale-out offering.
According to the FAQ it is possible now, see http://aws.amazon.com/rds/faqs/#86 :
Q: What types of replication does
Amazon RDS support and when should I
use each?
Amazon RDS provides two distinct replication options to serve different
purposes.
If you are looking to use replication to increase database
availability while protecting your
latest database updates against
unplanned outages, consider running
your DB Instance as a Multi-AZ
deployment. When you create or modify
your DB Instance to run as a Multi-AZ
deployment, Amazon RDS will
automatically provision and manage a
“standby” replica in a different
Availability Zone (independent
infrastructure in a physically
separate location). In the event of
planned database maintenance, DB
Instance failure, or an Availability
Zone failure, Amazon RDS will
automatically failover to the standby
so that database operations can resume
quickly without administrative
intervention. Multi-AZ deployments
utilize synchronous replication,
making database writes concurrently on
both the primary and standby so that
the standby will be up-to-date in the
event a failover occurs. While our
technological implementation for
Multi-AZ DB Instances maximizes data
durability in failure scenarios, it
precludes the standby from being
accessed directly or used for read
operations. The fault tolerance
offered by Multi-AZ deployments make
them a natural fit for production
environments; to learn more about
Multi-AZ deployments, please visit
this FAQ section.
If you are looking to take advantage of MySQL 5.1’s built-in
replication to scale beyond the
capacity constraints of a single DB
Instance for read-heavy database
workloads, Amazon RDS makes it easier
with Read Replicas. You can create a
Read Replica of a given “source” DB
Instance using the AWS Management
Console or CreateDBInstanceReadReplica
API. Once the Read Replica is created,
database updates on the source DB
Instance will be propagated to the
Read Replica. You can create multiple
Read Replicas for a given source DB
Instance and distribute your
application’s read traffic amongst
them. Unlike Multi-AZ deployments,
Read Replicas use MySQL 5.1’s built-in
replication and are subject to its
strengths and limitations. In
particular, updates are applied to
your Read Replica(s) after they occur
on the source DB Instance
(“asynchronous” replication), and
replication lag can vary
significantly. This means recent
database updates made to a standard
(non Multi-AZ) source DB Instance may
not be present on associated Read
Replicas in the event of an unplanned
outage on the source DB Instance. As
such, Read Replicas do not offer the
same data durability benefits as
Multi-AZ deployments. While Read
Replicas can provide some read
availability benefits, they and are
not designed to improve write
availability.
With Amazon RDS, you can use Multi-AZ deployments and Read Replicas
in conjunction to enjoy the
complementary benefits of each. You
can simply specify that a given
Multi-AZ deployment is the source DB
Instance for your Read Replica(s).
That way you gain both the data
durability and availability benefits
of Multi-AZ deployments and the read
scaling benefits of Read Replicas.