The specified Security Group and Parameter Group are not set in the RDS instance

If the Terraform apply execution times out during the RDS instance creation, the specified Security Group and Parameter Group is not set in the RDS instance.

The solution is to set the timeout in the aws_db_instance resource. When a multi-az RDS instance is launched from a snapshot, the process can take more than 55 minutes. The default value is 40 minutes.

resource "aws_db_instance" "default" {
...
  timeouts {
    create = "120m"
    delete = "120m"
  }
...
}

SQL Server AWS RDS instance ALARM FreeableMemory <=... MB

The SQL database servers use the available memory for caching to speed up the database operation. If we do not restrict the SQL database server memory usage, the operating system will not have enough memory to run. This setting is also necessary for an AWS RDS instance, otherwise, you will get the alert

ALARM FreeableMemory <=… MB

In AWS we can specify the maximum SQL server memory dynamically, so every RDS instance type will leave enough memory for the operating system regardless of the size of the available memory size. in this example, we will leave 1.5 GB (1536 MB) memory for the operating system so the default 1024 MB free memory alarm will not sound.

DBInstanceClassMemory returns the total memory size in bytes, so we need to convert the value to MB, to be able to set the value of “max server memory (mb)” to the correct number.

If you use Terraform to create your RDS instance, create a script with the aws_db_parameter_group resource to create a Parameter Group in your AWS account. You need to execute it once, as all RDS instances will use the same group.

resource "aws_db_parameter_group" "default" {

  name = "max-server-memory"
  family = "sqlserver-se-12.0"
  description = "DBInstanceClassMemory"

  parameter {
    name = "custom-sqlserver-se-12-0"
    value = "SUM({DBInstanceClassMemory/1048576},-1536)"
    apply_method = "immediate"
  }
}

In the RDS instance creation script assign the Parameter Group to the RDS instance and increase the timeout of the create and delete operations to make sure Terraform waits during the creation and deletion process.

resource "aws_db_instance" "default" {
...
  # Add the Max Server Memory parameter group to the instance
  parameter_group_name = "custom-sqlserver-se-12-0"
...
  timeouts {
    create = "120m"
    delete = "120m"
  }
...
}

 

 

 

Migrate databases to and from AWS RDS instances

Amazon Web Services do not provide tools to migrate data to, from and between AWS RDS instances.

There is a free utility that can do the job.

SQL Server Management Studio (SSMS)

Install Microsoft SQL Server Management Studio (SSMS), because the utility uses libraries from it.

  1. Download the installer for free from https://msdn.microsoft.com/en-us/library/mt238290.aspx

SQL Azure Migration Wizard

Installation

  1. Download the SQL Azure Migration Wizard from http://sqlazuremw.codeplex.com/
  2. Unzip the downloaded ZIP file into a folder on your hard drive
  3. Create a shortcut in your Start Menu for SQLAzureMW.exe

Migrate a database

  1. Start the SQL Azure Migration Wizard by executing the SQLAzureMW.exe file
  2. Select Database in the Analyze / Migrate section and click Next

Connect to the source database

  1. On the Connect to Server page
    1. Enter the address of the database server
    2. Select SQL Server Authentication
    3. Enter the database owner login name and password
    4. If you keep Master DB selected, the next screen will show the list of databases to select from
    5. To save the username and password select Save Login Information
    6. Click Connect

  2. Select the database to connect to and click Next
  3. Leave Script all database objects selected and click Next
  4. On the Script Wizard Summary page click Next
  5. Click Yes to start the read process
  6. On the Results Summary page select Auto Scroll Display to see the scrolling results
  7. When the read is done click Next

Connect to the target database

  1. Enter the connection properties of the target database server
  2. Select the target database
    1. To migrate the data into a new database click the Create Database button
    2. On mirrored RDS instances we cannot drop and recreate databases. To migrate data into an existing database
      1. Use SQL Management Studio to drop the existing tables to avoid key conflicts
      2. Select the target database on this page
  3. Click Next
  4. Click Yes to start the write process
  5. When the write process is done click Exit