One of our customers reported strange problem with MySQL having extremely poor performance when sync-binlog=1 is enabled, even though the system with RAID and BBU were expected to have much better performance. The problem could be repeated with SysBench as follows: ./sysbench –num-threads=2 –test=oltp –oltp-test-mode=complex –oltp-table-size=100000 –oltp-distinct-ranges=0 –oltp-order-ranges=0 –oltp-sum-ranges=0 –oltp-simple-ranges=0 –oltp-point-selects=0 –oltp-range-size=0 –mysql-table-engine=innodb –mysql-user=root –max-requests=0 [...]