Amazon RDS FAQs

General

Q: What is Amazon RDS?

Amazon Relational Database Service (Amazon RDS) is a web service that makes it easy to set up, operate, and scale a relational database in the cloud. It provides cost-efficient and resizable capacity, while managing time-consuming database administration tasks, freeing you up to focus on your applications and business.

Amazon RDS gives you access to the full capabilities of a familiar MySQL database. This means the code, applications, and tools you already use today with your existing MySQL databases work seamlessly with Amazon RDS. Amazon RDS automatically patches the database software and backs up your database, storing the backups for a user-defined retention period. You also benefit from the flexibility of being able to scale the compute resources or storage capacity associated with your relational database instance via a single API call. As with all Amazon Web Services, there are no up-front investments required, and you pay only for the resources you use.

Q: What is a database instance (DB Instance)?

You can think of a DB Instance as a MySQL 5.1 environment in the cloud with the compute and storage resources you specify. You can create and delete DB Instances, define/refine infrastructure attributes of your DB Instance(s), and control access and security via the Amazon RDS APIs and Command Line Tools. Multiple MySQL databases can be created on a given DB Instance.

Q: What does Amazon RDS manage on my behalf?

Amazon RDS manages the work involved in setting up a relational database, from provisioning the infrastructure capacity you request to installing the database software. Once your database is running on its own DB Instance, Amazon RDS automates common administrative tasks, such as performing backups and patching the database software that powers your DB Instance. Since Amazon RDS provides native database access, you interact with the relational database software (i.e. MySQL 5.1) as you normally would. This means you’re still responsible for managing the database settings that are specific to your application. You’ll need to build the relational schema that best fits your use case and are responsible for any performance tuning to optimize your database for your application’s workflow.

Q: When would I use Amazon RDS vs. Amazon EC2 Relational Database AMIs vs. Amazon SimpleDB?

Amazon Web Services provides a number of database alternatives for developers. Amazon RDS enables you to run a fully featured relational database while offloading database administration; Amazon SimpleDB provides simple index and query capabilities with seamless scalability; and using one of our many relational database AMIs on Amazon EC2 and Amazon EBS allows you to operate your own relational database in the cloud. There are important differences between these alternatives that may make one more appropriate for your use case.

See Running Databases on AWS for additional guidance on which solution is best for you.

Q: How do I get started with Amazon RDS?

To sign up for Amazon RDS, you must click the “Sign up for Amazon RDS” button on the Amazon RDS detail page and complete the sign-up process. You must have an Amazon Web Services account; if you do not already have one, you will be prompted to create one when you begin the Amazon RDS sign-up process. After you are signed up for RDS, please refer to the Amazon RDS documentation, which includes our Getting Started Guide.

Q: How do I create a DB Instance?

DB Instances are simple to create, using either the Amazon RDS Command Line Tools or APIs. Simply specify the instance identifier, database engine, compute class, storage, master user, and master user password with the rds-create-db-instance or CreateDBInstance API, and within minutes, your DB Instance is up and running.

Q: How do I access my running DB Instance?

Once your DB Instance is available, you can retrieve its endpoint via the DescribeDBInstance API. Using this endpoint you can construct the connection string required to connect directly with your DB Instance using your favorite database tool or programming language. In order to allow network requests to your running DB Instance, you will need to authorize access. For a detailed explanation of how to construct your connection string and get started, please refer to our Getting Started Guide.

Q: How many DB Instances can I run with Amazon RDS?

As of this point in time, you are limited to running twenty DB Instances. If your application requires more than twenty DB Instances, you can request additional DB Instances via the request form on the Amazon RDS detail page.

Q: How do I import data to Amazon RDS?

There are a number of simple ways to import data into Amazon RDS, such as with the mysqldump or mysqlimport utilities. For more information on data import and export, please refer to the Amazon RDS MySQL Data Import Guide.

Q: Which relational database engines does Amazon RDS support?

Amazon RDS currently supports MySQL 5.1 (Community Edition). The default database storage engine is InnoDB.

Q: Are my Amazon RDS databases replicated across multiple availability zones?

Amazon RDS is currently offered in a single availability zone. In the coming months we will make available a High Availability option for Amazon RDS, enabling you to provision synchronously replicated DB Instances in multiple availability zones (AZ’s), to protect against failure within a single location. In the unusual case where your DB Instance does fail, you can use the RestoreDBInstanceToPointInTime API to create a new DB Instance from the latest restorable time. The DB Instance backup data that enables restore operations is replicated geo-redundantly in multiple availability zones for greater levels of data durability. We encourage you to take advantage of the Amazon RDS automated backup feature and backup storage allocated at no additional charge to guard against data loss in the event of DB Instance failure.

Q: What is a maintenance window? Will my DB Instance be available during software maintenance?

Any system changes (such as patching the database software) or modifications you have requested (such as scaling DB Instance class or storage capacity) will be completed within a weekly four hour maintenance window. The only time we will take your DB Instance offline is for backups or software patching; patching should seldom require more than a fraction of your maintenance window, occurs infrequently, and is used only for patches that are security or durability related. If you did not specify a preferred maintenance window when creating your DB Instance, a default value is assigned (such as Sun:05:00-Sun:09:00 UTC for DB Instances in the US-East region). Ideally this window should fall at the time of lowest database usage and thus may need to be modified. If you wish to modify when maintenance is performed on your behalf, you can do so using the ModifyDBInstance API. Each of your DB Instances can have different preferred maintenance windows, if you so choose. For more information on using the APIs or command line interface to specify your maintenance window, please refer to the Amazon RDS Developer Guide.

Q: Does Amazon RDS always update the relational database software with critical patches? Can I opt out of particular patches?

Automatically performing critical updates to the MySQL database software powering your DB Instance is a core function of Amazon RDS and cannot be turned off. However, as previously mentioned, you can control the time of the maintenance window when patches are applied to minimize the operational impact of patching. At this point in time, you cannot opt-out of critical patches to the MySQL software. However, you will be informed about upcoming patches via the Amazon RDS forums.

Q: What should I do if my queries seem to be running slow?

You can access the MySQL slow query logs for your database to determine if there are slow-running SQL queries and, if so, the performance characteristics of each. For more information on accessing and querying the slow query table, please refer to the Amazon RDS Developer Guide. You may also want to check the CPU utilization metrics for your DB Instance via Amazon CloudWatch. High levels of CPU utilization can reduce query performance and in this case you may want to consider scaling your DB Instance class. For more information on monitoring your CPU utilization, read the Amazon RDS Monitoring Guide.

Billing

Q: How will I be charged and billed for my use of Amazon RDS?

You pay only for what you use, and there are no minimum or setup fees. You are billed based on:

• DB Instance hours – Based on the class (e.g. Standard Small, Large, Extra Large) of the DB Instance consumed. Partial DB Instance hours consumed are billed as full hours.
• Storage (per GB per month) – Storage capacity you have provisioned to your DB Instance. If you scale your provisioned storage capacity within the month, your bill will be pro-rated.
• I/O requests per month – Total number of storage I/O requests you have.
• Backup Storage – Backup storage is the storage associated with your automated database backups and any active database snapshots you have taken. Increasing your backup retention period or taking additional database snapshots increases the backup storage consumed by your database. Amazon RDS provides backup storage up to 100% of your provisioned database storage at no additional charge. For example, if you have 10GB-months of provisioned database storage, we will provide up to 10GB-months of backup storage at no additional charge. Based upon our experience as database administrators, the vast majority of databases require less raw storage for a backup than for the primary data set, meaning that most customers will never pay for backup storage. Backup storage is only free for active DB Instances.
• Data transfer –Internet data transfer in and out of your DB Instance.

For Amazon RDS pricing information, please visit the pricing section on the Amazon RDS product page.

Q: When does billing of my Amazon RDS DB Instances begin and end?

Billing commences for a DB Instance as soon as the DB Instance is available. Billing continues until the DB Instance terminates, which would occur upon deletion or in the event of instance failure.

Q: What defines billable Amazon RDS instance hours?

DB Instance hours are billed for each hour your DB Instance is running in an available state. If you no longer wish to be charged for your DB Instance, you must terminate it to avoid being billed for additional instance-hours. Partial DB Instance hours consumed are billed as full hours.

Q: Why does additional backup storage cost more than allocated DB Instance storage?

The storage provisioned to your DB Instance for your primary data is located within a single availability zone. When your database is backed up, the backup data (including transactions logs) is geo-redundantly replicated across multiple availability zones to provide even greater levels of data durability. The price for backup storage beyond your free allocation reflects this extra replication that occurs to maximize the durability of your critical backups.

Hardware and Scaling

Q: How do I determine which initial DB Instance class and storage capacity are appropriate for my needs?

In order to select your initial DB Instance class and storage capacity, you will want to assess your application’s compute, memory and storage needs. For more guidelines on picking the right DB Instance class and storage capacity, please refer to the Amazon RDS DB Instance Sizing Guide

Q: How do I scale the compute resources and/or storage capacity associated with my RDS database instance?

You can scale the compute resources and storage capacity allocated to your DB Instance with the ModifyDBInstance API. Memory and CPU resources are modified by changing your DB Instance class, and storage available is changed when you modify your storage allocation. Please note that when you modify your DB Instance class or allocated storage using the ModifyDBInstance API, your requested changes will be applied during your specified maintenance window. Alternately, you can use the “apply-immediately” flag to apply your scaling requests immediately. Bear in mind that any other pending system changes will be applied as well.

Monitor the compute and storage resource utilization of your DB Instance, for no additional charge, via Amazon CloudWatch. You can access metrics such as CPU utilization, storage utilization, and network traffic. To learn more about monitoring your active DB Instances, read the Amazon RDS Monitoring Guide.

Q: Will my DB Instance remain available during scaling?

The storage capacity allocated to your DB Instance can be increased while maintaining DB Instance availability. However, when you decide to scale the compute resources available to your DB Instance up or down, your database will be temporarily unavailable while the DB Instance class is modified. This period of unavailability typically lasts only a few minutes, and will occur during the maintenance window for your DB Instance, unless you specify that the modification should be applied immediately.

Q: How can I scale my DB Instance beyond the largest DB Instance class and maximum storage capacity?

Amazon RDS supports a variety of DB Instance classes and storage allocations to meet different application needs. If your application requires more compute resources than the largest DB Instance class or more storage than the maximum allocation, you can implement partitioning, thereby spreading your data across multiple DB Instances.

Automated Backups and Database Snapshots

Q: What is the difference between RDS automated backups and DB Snapshots?

Amazon RDS provides two different methods for backing up and restoring your DB Instance(s): automated backups and database snapshots (DB Snapshots). The automated backup feature of Amazon RDS automatically performs a daily backup of your data (during your preferred backup window) and captures transaction logs (constantly). Amazon RDS retains backups of a DB Instance for a limited, user-specified period of time called the retention period, which by default is one day; your database can later be recovered to any point in time within the retention period, up to the last available transaction log. You can use the DescribeDBInstances API to return the latest restorable time for you DB Instance(s). DB Snapshots are user-initiated and enable you to back up your DB Instance in a known state as frequently as you wish, and then restore to that specific state at any time. DB Snapshots can be created with the CreateDBSnapshot API and are kept until you explicitly delete them with the DeleteDBSnapshot API. Please note: When you perform a restore operation to a point in time or from a DB Snapshot, a new DB Instance is created with a new endpoint (the old DB Instance can be deleted with the DeleteDBInstance API, if so desired).

Q: Do I need to enable backups for my DB Instance or is it done automatically?

By default and at no additional charge, Amazon RDS enables automated backups of your DB Instance with a 1 day retention period. Free backup storage is limited to the size of your provisioned database and only applies to active DB Instances. For example, if you have 10GB-months of provisioned database storage, we will provide at most 10GB-months of backup storage at no additional charge. If you would like to extend your backup retention period beyond one day, you can do so using the CreateDBInstance API (when creating a new DB Instance) or ModifyDBInstance API (for an existing DB Instance). You can use these APIs to change the RetentionPeriod parameter from 1 to the desired number of days. For more information on automated backups, please refer to the Amazon RDS Developer Guide.

Q: What is a backup window and why do I need it? Is my database available during the backup window?

The preferred backup window is the user-defined period of time during which your DB Instance is backed up. Amazon RDS uses these periodic data backups in conjunction with your transaction logs to enable you to restore your DB Instance to any point in time during your retention period. During the backup window, storage I/O may be suspended while your data is being backed up. This typically lasts a few minutes.

Q: How do I manage the retention of my automated backups and DB Snapshots?

You can use the ModifyDBInstance API to manage the period of time your automated backups are retained by modifying the RetentionPeriod parameter. If you desire to turn off automated backups altogether, you can do so by setting the retention period to 0 (not recommended). You can see a list of the user-created DB Snapshots for a given DB Instance using the DescribeDBSnapshots API and delete snapshots with the DeleteDBSnapshot API.

Q: What happens to my backups and DB Snapshots if I delete my DB Instance?

When you delete a DB Instance, you have the ability to specify whether a final DB Snapshot is created upon deletion, which enables a DB Snapshot restore of the deleted database instance at a later date. All previously created DB Snapshots of your DB Instance will be retained and billed at $0.15 per GB-month, unless you choose to delete them with the DeleteDBSnapshot API.

Security

Q: What is an Amazon RDS master user account and how is it different from an AWS account?

To begin using Amazon RDS you will need an AWS developer account. If you do not have one prior to signing up for Amazon RDS, you will be prompted to create one when you begin the sign-up process. A master user account is different from an AWS developer account and used only within the context of Amazon RDS to control access to your DB Instance(s). The master user account is a native database user account which you can use to connect to your DB Instance. You can specify the master user name and password you want associated with each DB Instance when you create the DB Instance. Once you have created your DB Instance, you can connect to the database using the master user credentials. Subsequently, you may also want to create additional user accounts so that you can restrict who can access your DB Instance.

Q: What privileges are granted to the master user for my DB Instance?

The default privileges for the master user include: create, drop, references, event, alter, delete, index, insert, select, update, create temporary tables, lock tables, trigger, create view, show view, alter routine, create routine, execute, trigger, create user, process, show databases, grant option.

Q: Is there anything different about user management and privileges with Amazon RDS?

No, everything works the way you are familiar with when using a relational database. For example, when running a DB Instance with MySQL 5.1, you will use commands like CREATE USER, RENAME USER, GRANT, REVOKE, SET PASSWORD, or directly modify the MySQL schema tables.

Q: How do I control network access to my DB Instance(s)?

Amazon RDS allows you to control access to your DB Instances using database security groups (DB Security Groups). A DB Security Group acts like a firewall controlling network access to your DB Instance. By default, network access is turned off to your DB Instances. If you want your applications to access your DB Instance you can set your DB Security Group to allow access from specific EC2 Security Groups or IP ranges. This process is called ingress. Once ingress is configured for a DB Security Group, the same rules apply to all DB Instances associated with that DB Security Group.

DB Parameter Groups

Q: Can programs running on servers in my own data center access Amazon RDS databases?

Yes. You have to intentionally turn on the ability to access your database over the Internet by granting permissions to your Amazon RDS DB Security Group(s) for access over the Internet. You can authorize access for only the specific IP’s, IP ranges, or subnets corresponding to servers in your own data center.

Q: How do I choose the right configuration parameters for my DB Instance(s)?

Amazon RDS by default chooses the optimal configuration parameters for your DB Instance taking into account the DB Instance’s compute resource and storage capacity. However, if you want to change them, you can do so using our configuration management APIs. Please note that changing configuration parameters from recommended values can have unintended effects, ranging from degraded performance to system crashes, and should only be attempted by advanced users who wish to assume these risks. For more information on changing parameters, please refer to the Amazon RDS documentation.

Q: What are DB Parameter groups? How are they helpful?

A database parameter group (DB Parameter Group) acts is a “container” for engine configuration values that can be applied to one or more DB Instances. If you create a DB Instance with a MySQL engine and don’t specify a particular DB Parameter Group, a “default.MySQL5.1” DB Parameter Group is used. This default group contains engine defaults and Amazon RDS system defaults optimized for the DB Instance you are running. However, if you want your DB Instance to run with your custom-specified engine configuration values, you can simply create a new DB Parameter Group, modify the desired parameters, and modify the DB Instance to use the new DB Parameter Group. Once associated, all DB Instances that use a particular DB Parameter Group get all the parameter updates to that DB Parameter Group. For more information on configuring DB Parameter Groups, please read the Amazon RDS DB Parameter Group Deployment Guide.

Q: How do I see the current setting for my parameters for a given RDS DB Parameter Group?

You can use the Amazon RDS APIs or command line tools to see information about your DB Parameter Groups and their corresponding parameter settings.