Changing instance type on MMS AWS provisioned Mongo install

[Marco Ocana]

Hi,

Once we have setup a replica set using MMS on AWS: what is the easiest and/or quickest way to change the AWS instance type while keeping your data?

Specifically: we are not sure what we should be using for the size/instance category AWS instance. And of course, the bigger the instance type, the bigger the bill.
We want to be able to upgrade or downgrade the instance type when we have a feel for what happens in production.
Some possibilities that occurred to me, but have not been able to get to work:
1) Unmount the external EBS volume and mount it on the new instance.
2) Add the new instance to the replica set, wait for synchronization, and then remove the old instance or instances from the set.

Thanks

Marco

[Stephen Steneker]

Hi Marco,

Either of these approaches would be valid if you are moving to different instance types in the same availability zone. Stopping and remounting EBS volumes is going to be faster than re-syncing your data if you are using the same type of storage; adding new instances may allow you to do more QA before retiring/affecting the old instance.

One factor you should be aware of is that in addition to changing CPU & memory allocations, different instance types can also affect your EBS and network bandwidth:

 http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ebs-ec2-config.html

For tuning your deployment you should also consider the production notes and EC2 info in the MongoDB manual:

 http://docs.mongodb.org/manual/administration/production-notes/

 http://docs.mongodb.org/ecosystem/platforms/amazon-ec2/

Regards,

Stephen