Working with replication instances

This page was generated from content adapted from the AWS Developer Guide

Choosing replication instance types

  • Important If you use a dms.t3.micro instance under the AWS Free Tier offer and use it in unlimited mode, charges might apply. In particular, charges might apply if your average utilization over a rolling 24-hour period exceeds the baseline utilization of the instance. For more information, see Baseline utilization in the Amazon EC2 User Guide for Linux Instances. T3 instances launch as unlimited by default. If the average CPU usage over a 24-hour period exceeds the baseline, you incur charges for surplus credits. In some cases, you might launch T3 Spot Instances as unlimited and plan to use them immediately and for a short duration. If you do so with no idle time for accruing CPU credits, you incur charges for surplus credits. We recommend that you launch your T3 Spot Instances in standard mode to avoid paying higher costs. For more information, see Surplus credits can incur charges, T3 Spot Instances, and Standard mode for burstable performance instances in the Amazon EC2 User Guide for Linux Instances.

Replication engine versions

  • Note We recommend that you stop all tasks before upgrading the Replication Instance. If you don't stop the task, AWS DMS will stop the task automatically before the upgrade. If you stop the task manually, you will need to start the task manually after the upgrade is complete. Upgrading the replication instance takes several minutes. When the instance is ready, its status changes to available.

  • Note Upgrading the replication instance takes several minutes. You can view the replication instance status using the following command.

Setting up a network for a replication instance

  • Note Since an IP address can change as a result of changes to underlying infrastructure, we recommend you use a VPC CIDR range, or route your replication instance outbound traffic through a NAT GW associated Elastic IP. For more information about creating a VPC, including a CIDR block, see Work with VPCs and subnets in the Amazon Virtual Private Cloud User Guide. For more information about Elastic IP addresses, see Elastic IP addresses in the Amazon Elastic Compute Cloud User Guide.

Modifying a replication instance

  • Note If you choose to apply changes immediately, any changes in the pending modifications queue are also applied. If any of the pending modifications require downtime, choosing Apply changes immediately can cause unexpected downtime.

Rebooting a replication instance

  • Note After a reboot forces a failover from one Availability Zone to another, the Availability Zone change might not be reflected for several minutes. This lag appears in the AWS Management Console, and in calls to the AWS CLI and AWS DMS API.

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