I led a painful migration a couple of years ago and can share some tips.
It's not clear whether v2 is already in production somewhere else. If it is not, you better wait until 1) the v2 data model has really been finalized and in prod and 2) key resources can be made available to the migration team. We were forced to begin the migration before the new product was complete and it was just plain impossible. We had to start all over every quarter.
- Migrations are very difficult to estimate. Any optimistic estimate will bite back. Hold off as much as you can, and ensure appropriate buffers if you really have to.
- ensure that the 8 clients have an identical v1 data model (tables, constraints, etc). If that is not the case, remember you will run n migrations, not 1.
- You need a team with knowledge of both v1 and v2 data models, as well as business domain know-how. There are many decisions that need to be made and you need the right people to be around.
- Not everything has to be migrated. Trying to migrate 100% is a common mistake: engage with the customers to understand what's the minimum that legally and operationally has to be migrated, especially if the v1 system has been in production for many years.
- Data migration is a iterative process, and the last thing you want to is to manually QA every iteration. You need to develop tests that will provide a reasonable data integrity assurance.
- Dashboards showing data migrated, failing/ok tests, remaining tables, etc. help communicate status and track progress.
- Customers will need to be involved during the whole project. You need them to commit to making people available that can quickly answer questions to unlock you dev teams. ideally, you want to create a single team. Make sure that decisions are traced and versioned.
- Performance matters. Discuss the performance requirements upfront. Our process was very, very slow and we found out a bit too late that the customer would not tolerate such down time. Also, discuss "when" ok to migrate, how to rollback in case of failure, etc.
Developed a solution (File System Filter Driver) to prevent ransomware from encrypting users' files. It's 70% done but I have recently accepted a position at a company and will not have time to build a full fledged product. I have tested it against major ransomware variants and it has proved very effective. I am looking to license either object or source code.
I am 10 years younger than your father and had a though time finding a job too. I have a bachelor in Information Engineering, founded and sold two successful startups in the InfoSec space, have raised venture capital and love programming, but still took me about a year to find a job. Granted, I wasn't ready to compromise too much, but heck, as the months go by, it becomes more and more frustrating, especially when age seems to be the #1 discriminating factor.
I am moved by all the support shown here to your father: hopefully it will help him boost his morale. I encourage you to keep digging too - it's payback time.