What are the respective advantages/limitations of Amazon RDS vs. EC2 with MySQL? [closed]

Answer 1

I had the same question this weekend. There is a 4 hour downtime window per week for RDS where they do maintenance. RDS seemed more expensive if you can get away with a micro instance of EC2. (This is true of test instances which has minimum traffic) I also wasn't able to change the timezone of the RDS instance because I dont have permission.

I am now actually looking at http://xeround.com/ which is mysql on EC2 by another company. They do not use InnoDB, instead they have their own engine called IDG. I am just starting to investigate that but they are in BETA and will give 500MB of space.

Answer 2

MySQL on EC2 vs RDS MySQL

Advantages of MySQL on EC2 Amazon EC2 Inter Region Replication

Copy Snapshots across Amazon EC2 regions

RAID 0 with EBS Striping in MySQL EC2

More than 3TB of Disk space ( You will not need this for your size) can be attached on MySQL on EC2.

Disadvantages of MySQL on EC2

Configuration, Monitoring and Maintenance compared to RDS

Point in time backups available in RDS

IOPS lesser than RDS MySQL ( even after RAID 0) currently, 10800 with 6 disks for MySQL on EC2 whereas 12500 IOPS 16KB on RDS MySQL

Answer 3

Regarding the maintenance window question. If you use Multi-AZ then RDS will create a standby replica in another availability zone so that there's no down time for maintenance and you protect yourself against a zone failure.

That's what I'm planning to do in the next week or so. Of course it's going to cost you more but I haven't worked that bit out yet.

Answer 4

We chose to use EC2 MySQL instances because we have a high read volume and need master-slave replication. Of course, you can spin up multiple RDS instances and setup MySQL replication between them yourself, but we use Scalr.net, which manages that for you using EC2 instances.

Basically, we just tell Scalr how many MySQL instances we want at it keeps them up, automates the setup of replication, handles automatic failover of slave promotion to master if the master gets terminated etc. It does both SQL dump backups and EBS volume snapshots of the master. So, when it needs to create a new slave, it automatically temporarily mounts an EBS volume of the last master snapshot to initialize the slave DB, then starts replication from the appropriate point. All point and click :) (and no, I don't work for Scalr or anything. Scalr is available as Open Source if you don't want to use their service)

Answer 5

RDS is not really a high availability system. Read the fine print in the RDS faq. During a failover event it can take up to 3 minutes to failover. Additional amazon will decide it needs to "upgrade" your rds instance and do a failover at that point which will take your database down for "up to 3 minutes" (our experience is that it can take a longer than that).

RDS high availability is very different than master - master or master - slave replication and is much slower. They don't use mysql replication but uses some kind of ebs replication. So in a failover situation it will mount the ebs on the backup machine, start mysql, wait for mysql to do failure recover (hopefully nothing got corrupted too bad), then do a dns switch.

I hope this helps you with you evaluation.

Answer 6

I have been trying out RDS for a few months and here are some issues I have:

1. Using SQL profiler is tricky. Since you cannot connect profiler directly to the server, you have to run some stored procedures to create a log file that you can analyze. While they offer some suggestions about how that is done, it is far from user friendly. I would only recommend that you have a certified SQL professional do this kind of work.

2. while Amazon backs up your instance, you cannot restore an individual database. I have a web app with several separate customer-specific databases and my solution was to launch an EC2 instance with SQL running on it to attach to the production RDB database and import the data and then back it up on the EC2 instance. The other solution was to use a 3rd party tool that creates a massive SQL script (on the app server) that will recreate the schema and populate the data back to a restore point.