Code review comment for lp:~sergei.glushchenko/percona-server/ps56-univ-log-archive

Will post couple of questions here
1. This implementation is different from described in https://blueprints.launchpad.net/percona-server/+spec/log-archiving, do we need to disapprove this blueprint and create new one, or just change existing one to describe current implementation?
2. This "I would like to have corresponding binary log position for log archive.
This will allow to have point in time recovery with binary logs." has not been implemented in original implementation and there is no comments about it in previous MP. Do we need this feature?
3. Do we need variable (like have_xtra_log_archiving) to indicate that server has archiving support?
4. Do we really need to be able enable/disable archiving at runtime as BP above describes? We should handle partially written archives somehow in this case.