Every cloud architecture diagram you've ever drawn for a "modernize the legacy system" project probably has the same box in it: a sync job. Something that watches an old file share and copies what it finds into S3, so the new, shiny, event-driven, AI-powered part of the stack has something to read. That box is a lie we tell ourselves. It says "the data is now in the cloud." What it actually means is: there are now two copies of the data, and something has to keep them the same. This post...