[drwxrwxrwt]

It took a while. cant put a number cause a lot of it was done in spurts between other projects. altogether the project took about four months, but that included refactoring a lot of old code to play nice with mirrored writes and developing some framework level components. and waiting for hardware. and waiting for innodb conversion. and building setting up proper monitoring and alerting. future projects like that will take fraction of the time. Migration and verification itself took about 2 weeks. Yes, passes got proportionally quicker. first took almost a week, last few hours. we did not crank the speed to the max though as we wanted to keep the load low and we had time.

thanks for the link, will check it out