Percona Server 5.6.11-60.3 has introduced a new feature called Log Archiving for XtraDB. This feature makes copies of the old log files before they are overwritten, thus saving all the redo log for a write workload.
When log archiving is enabled, it duplicates all redo log writes in a separate set of files in addition to normal redo log writing, creating new files as necessary.
Archived log file name format is ib_log_archive_startlsn. The start LSN marks the log sequence number when the archive was started. An example of the archived log files should look like this: