I have created a WPF application and I am using Sync Framework 2.1. My database size is more than 5GB. It is taking too much time to sync database first time. If connectivity is down then it stop syncronization and goes into hang state.
you can create a pre-populated database and distribute that.
you can use GenerateSnapshot if you want to distribute an SDF or if it's SQL Server, you can do a backup, restore on the other synching partner and running PerformPostRestoreFixup.