Amazon RDS Custom FAQs

• The Amazon RDS Custom agent is a critical component for ensuring RDS Custom functionality. If you uninstall this agent, the support perimeter will be triggered after 30 seconds and will move the DB instance outside the support perimeter.
  
• AWS Systems Manager Agent (SSM Agent) is another critical component that enables RDS Custom to run commands on the host remotely. If you uninstall the SSM Agent, the RDS Custom agent will try to recover by starting the SSM Agent. A support perimeter check will be triggered, and after three minutes of unsuccessful recovery, the SSM Agent will move the DB instance outside the support perimeter.
  

• The Amazon RDS Custom agent is a critical component for ensuring RDS Custom functionality. If you uninstall this agent, the support perimeter will be triggered after one minute and will move the DB instance outside the support perimeter.
  
• AWS Systems Manager Agent (SSM Agent) is another critical component that enables RDS Custom to run commands on the host remotely. If you uninstall the SSM Agent and the host becomes unreachable to the support perimeter, then your DB instance will be placed outside of the perimeter; if there is customer activity on the instance, this information is retrieved via events. If there is no customer activity on the host, recovery will be attempted first by rebooting the host. If that doesn’t fix the issue, the EC2 host will be stopped and started, and if that also doesn’t work, the EC2 host will be replaced.

With Amazon RDS Custom for SQL Server, you have two SQL Server licensing options: License Included (LI) and Bring Your Own Media (BYOM).

With the LI option, you can create RDS Custom for SQL Server instances with Windows and SQL Server licenses supplied by AWS. AWS manages the licensing for you; all you need to do is pay for the instances that you provision. LI is available for SQL Server Web Edition, Standard Edition, and Enterprise Edition.

With the BYOM option, you can leverage your existing SQL Server licenses with Amazon RDS Custom for SQL Server, subject to Microsoft’s licensing terms. The License Mobility Page offers detailed information on the process. Microsoft requires that customers complete and send a License Mobility verification form.

Q: Do I need active Software Assurance and License Mobility benefits to use my Microsoft SQL Server licenses with Amazon RDS Custom for SQL Server?

Yes. SQL Server licenses with active Software Assurance is needed for License Mobility and to be deployed on RDS Custom for SQL Server. For additional details on bringing SQL Server licenses with active Software Assurance to RDS Custom for SQL Server, please see the License Mobility page on the AWS site.

Q: How do I know how many SQL Server licenses to bring in on RDS Custom?

If you are licensing SQL Server under Microsoft’s License Mobility through Software Assurance, the number of licenses required varies based on the instance type, version of SQL Server, and the Microsoft licensing model you choose. To assist with calculating licensing needed under the Microsoft Product Terms, AWS provides this virtual representation of hardware threads table by instance type.

Q: How do I get started with BYOM with Amazon RDS Custom for SQL Server?

With the BYOM licensing option, you must first verify your SQL Server licensing with License Mobility through Software Assurance in order to use your licenses with Amazon RDS Custom. Then, go to the Amazon RDS Custom for SQL Server BYOM documentation page that includes details on how to get started.

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

Amazon RDS Custom 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 Custom enables point-in-time recovery of your DB instance. When automated backups are turned on for your DB instance, Amazon RDS Custom automatically performs a full daily snapshot of your data (during your preferred backup window) and captures transaction logs (as updates to your DB instance are made). When you initiate a point-in-time recovery, transaction logs are applied to the most appropriate daily backup in order to restore your DB instance to the specific time you requested. Amazon RDS retains backups of a DB Instance for a limited, user-specified period of time called the retention period, which by default is 7 days but can be set to up to 35 days. You can initiate a point-in-time restore and specify any second during your retention period, up to the Latest Restorable Time. You can use the DescribeDBInstances API to return the latest restorable time for your DB instance, which is typically within the last five minutes. Alternatively, you can find the Latest Restorable Time for a DB instance by selecting it in the AWS Management Console and looking in the “Description” tab in the lower panel of the Console.

DB snapshots are user-initiated and allow 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 AWS Management Console, CreateDBSnapshot API, or create-db-snapshot command and are kept until you explicitly delete them.

The snapshots which Amazon RDS Custom performs for enabling automated backups are available to you for copying (using the AWS console or the copy-db-snapshot command) or for the snapshot restore functionality. You can identify them using the "automated" snapshot type. In addition, you can identify the time at which the snapshot has been taken by viewing the "Snapshot Created Time" field. Alternatively, the identifier of the "automated" snapshots also contains the time (in UTC) at which the snapshot has been taken.

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 if so desired). This is done to allow you to create multiple DB instances from a specific DB snapshot or point in time.

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

By default, Amazon RDS Custom enables automated backups of your DB instance with a 7-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 100 GB of provisioned database storage over the month, we will provide 100 GB-months of backup storage at no additional charge.

If you would like to modify your backup retention period, you can do so using the console or the CreateDBInstance API (when creating a new DB instance) or the ModifyDBInstance API (for existing instances). You can use these APIs to change the RetentionPeriod parameter to any number from 1 to the desired number of days. The value can't be set to 0.

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 Custom uses these periodic data backups in conjunction with your transaction logs so you can restore your DB instance to any second during your retention period, up to the LatestRestorableTime (typically up to the last few minutes). During the backup window, storage I/O may be briefly suspended while the backup process initializes (typically under a few seconds) and you may experience a brief period of elevated latency.

Q: Where are my automated backups and DB snapshots stored and how do I manage their retention?

Amazon RDS DB snapshots and automated backups are stored in Amazon Simple Storage Service (Amazon S3).

You can use the AWS Management Console, the ModifyDBInstance API, or the modify-db-instance command to manage the period of time your automated backups are retained by modifying the RetentionPeriod parameter. You can manage your user-created DB snapshots via the "snapshots" section of the Amazon RDS Console. Alternatively, you can see a list of the user-created DB Snapshots for a given DB instance using the DescribeDBSnapshots API or describe-db-snapshots command and delete snapshots with the DeleteDBSnapshot API or delete-db-snapshot command.

Q: Why do I have more automated DB snapshots than the number of days in the retention period for my DB instance?

It is normal to have one or two more automated DB snapshots than the number of days in your retention period. One extra automated snapshot is retained to ensure the ability to perform a point-in-time restore to any time during the retention period. For example, if your backup window is set to one day, you will require two automated snapshots to support restores to any time within the previous 24 hours. You may also see an additional automated snapshot as a new automated snapshot is always created before the oldest automated snapshot is deleted.

Q: What happens to my backups and DB snapshots if I delete my DB instance?

When you delete a DB instance, Amazon RDS Custom retains all manually created DB snapshots after the DB instance is deleted. Refer to the pricing page for details of backup storage costs.

Automated backups are deleted when the DB instance is deleted, you can retain it with no delete-automated-backups parameter or select retain automation backed in the AWS console.