在将我的Web应用托管在云上时，我应该在db2实例上安装数据库还是应该使用RDS服务？

Question

While hosting my web app on cloud, should I install my db on the EC2 instance or should i use RDS service ? Some points come up :

1. Backing up would be automatic as EC2 instances are also backed up.
2. Wouldn't automatic scaling of resources compensate for any automatic scaling of db that RDS would provide ?

Answer 1

You can do either, and I have done both, but the absolute better practice is to use RDS for your database and EC2 for the websites, unless you have a really good reason not to (and if you are not sure if you have a good reason, then you probably don't).

I ran DB's on the instances using SQL Server for years, for a few low-traffic sites, and had no problems. I finally moved the last of these off of my EC2 instances and into RDS and wish I had done in years ago.

For a small, low-traffic site, you can get away with it, but as traffic picks up on your site, and you want to add the ability to autoscale your front-end, keeping the database on the instance is no longer an option. When you have upto 5-10-20 EC2 web instances balancing web traffic, and you want to add or remove instances dynamically to conserve resource (ie money), you'll be really happy the database is not on the single instance.

Besides that the automatic backups, the ability to restore to point-in-time, and they ability to take an RDS snapshot, and spin up a new RDS instance for development or testing purposes is really convenient.

Ultimately, everything that RDS does for you, you could do for yourselve using a fleet of EC2 instances, and a lot of time and money, but like I said, if you don't have the time, money or expertise (or the compelling reason) to set that redundancy up youself, then why bother.