We are replacing an old metrics storage system with scaling issues. How would you migrate the data without interrupting live traffic or losing any internal data?

"The whole process took about three months from the first screen in late November or early December to finishing in mid-March. Apple felt tighter than other companies because I had two real screens before the onsite, and the engineer screen was already basically an in-depth system design round. Every onsite round was tied pretty closely to the actual job on this observability team, especially storage migration, host cost, and working across a matrix organization. The most unusual part for me was the cross-org partnership round with a cost management stakeholder, and the so-called code review that turned into live coding from scratch. After the loop I waited about four weeks and heard they were still interviewing other candidates, which matched the feeling that they were being very selective about exact fit for this role."