I'm developing for a Filemaker intensive environment -- we have roughly 80 GB worth of data, 30-35 simultaneous users, and a number of related databases -- and the obstacle I'm running into is being unable to make modifications to even the smallest of tables without locking everyone up. Something as simple as adding a single text field to a table with just one record can take 20-30 minutes, if not more, and while that addition is being processed, every user in any of the databases will lock.

Best practices suggests working on back-ups to know exactly what needs to be done and applying changes before or after hours, but in most cases this slows development to a an appallingly slow crawl. Figuring things out on a back-up first helps, but the changes still need to be applied. With updates running over night and the way schedules are staggered here, there's really no good time to add fields and make these changes unless it's between midnight and 3AM, which just isn't feasible. Replacing files doesn't really work either, as these users are working in live data -- replacing a file means then having to do some sort of import/export to sync new information, which ends up being a time-consuming chore in itself.

Has anyone had a similar experience that can help shed some light on techniques that may be helpful? I've got a stack of projects that need to move forward, but I'm absolutely bashing my head against a wall trying to get things done without locking up end-users.

I've lived this as well. You can lock an entire table in Define Database. That means New Record fails! We error trap for this failure. There is no trick, and possibly you need to schedule down time for big changes (which in your case may be one new field in a huge table).

Here's a good thread on the subject

http://fmforums.com/forum/topic/82152-dev-best-practices-devstagingprod-migrations/page__fromsearch__1