On AWS, I have an EC2 instance for my database server with an attached 250GB EBS volume (200GB of actual data) for data storage. This volume has not been previously snapshotted.
I need to move this volume to another availability zone. I'm debating on the best approach. The server is fairly active, with a high number of writes and updates.
I take the website offline, and stop the database server. I start the snapshot, and once complete, launch a volume based on the snapshot in the new availability zone. I would estimate about 4 hours of downtime as I wait for the snapshot to finish.
I'm unsure if this would be more efficient. I take a snapshot of the volume while the site stays online. This will likely take 5 or 6 hours, but there is no downtime yet. The snapshot is obviously outdated by the time it finishes (and potentially corrupt?). I then take the website offline, stop the database server, and similar to above, create a new snapshot and volume. Since the second snapshot should only need to copy data that was modified in those 5 or 6 hours, I'm assuming I won't have 4 hours of downtime, but the snapshot will be much faster. Is this correct?
Thanks for the help.