Migration VMs versus Replication of VMs on AWS

Migration Only

For just migration capabilities, we can use vCenter plugin for vCenter (the on premises piece). This will not do ongoing replication.

Ongoing Replication

For ongoing replication, we use Server Migration Service.

SQL Server Only Replication

If all you care about is SQL Server replication, then you can use either native SQL Server Replication or AWS Data Migration Service.

Native SQL Server Replication (Always On Replication)

No real downsides – unless going from an unencrypted to an encrypted (or vice versa) database. In that case, this will not work

AWS DMS – Bulk Load Data with Ongoing Replication

1. Tasks with Migration Validation
2. Tasks can pick up where they left off in case of network outages etc.
3. Can go to Multi AZs as well  – if one AZ DMS service is down, the other one picks up the replication
4. Can also go to Aurora or Redshift directly instead of RDS

Steps –  DMS Service

1. Create a Replication Instance
2. Connect a SRC and TARGET database
3. Create Tasks

Steps – Source SQL Server

1. Enable Replication for the DB using sp_replicationdboption
2. Create a publication artefact with a 1 = 0 filter for the database (for logging all transactions to txaction log)
3. Use fn_dblog() and fn_dump_dblog() functions to read changes from the transaction log to the LSN

DMS Pricing

https://aws.amazon.com/dms/pricing/