… port=3306 innodb_buffer_pool_size = 30G innodb_flush_method = O_DIRECT innodb_log_file_size = 2000M innodb_log_files_in_group… = 8 innodb_write_io_threads = 8 innodb_io_capacity = 5000 sync_binlog=0 max_connections=5000 table_open_cache=5000 table…
Post: SHOW INNODB STATUS walk through
July 17, 2006 By 40 Comments
… allocated in it and how frequently threads are signaled using sync array. These counters can be used to represent frequency with… Innodb needs to fall back to OS Wait. There is direct information about OS waits as well – you can see “OS…, aio writes: 0, ibuf aio reads: 0, log i/o‘s: 0, sync i/o‘s: 0 Pending flushes (fsync) log: 0; buffer…
Post: ext4 vs xfs on SSD
March 15, 2012 By 26 Comments
… in ext3, where IO gets serialized per i_node in O_DIRECT mode (check for example Domas’s post) However from the… see, that ext4 still has problem with O_DIRECT. There are results for “single file” with O_DIRECT case (sysbench fileio 16 KiB blocksize…=on –file-num=1 –file-extra-flags=direct –file-fsync-freq=0 –file-io-mode=sync –file-block-size=16384 –report-interval…
Comment: Is there room for more MySQL IO Optimization?
January 10, 2013 By 11 Comments
… often you’re calling fsync() within your code, the real sync to the disk will be involved not more frequent than…, etc.) so, O_DIRECT is giving a workaround here from all these problems (and again, should be used combined with O_SYNC flag to…’ll be more *safe* when using O_DIRECT, while may still go faster with buffered I/O.. – but there is no silver bullet…
Comment: New Forum Categories: Help Wanted, For Hire
March 5, 2013 By 1 Comment
…_format=MIXED log-slave-updates log-bin=mdmp_freehold_binlog sync_binlog=1 relay-log=mdmp_freehold_relaylog max_relay_log… innodb_flush_log_at_trx_commit=1 innodb_flush_method=O_DIRECT innodb_thread_concurrency=16 innodb_buffer_pool_size = 4500M innodb… innodb_flush_log_at_trx_commit=1 innodb_flush_method=O_DIRECT innodb_thread_concurrency=16 innodb_buffer_pool_size = 4500M innodb…
Post: Can Innodb Read-Ahead reduce read performance ?
June 26, 2007 By 2 Comments
… INNODB STATUS: ——– FILE I/O ——– I/O thread 0 state: waiting for i/o request (insert buffer thread) I/O thread 1 state: waiting…, aio writes: 0, ibuf aio reads: 0, log i/o‘s: 0, sync i/o‘s: 0 Pending flushes (fsync) log: 0; buffer… is poor read-ahead performance plus multiple threads doing scattered O_DIRECT (so no OS read-ahead) single page reads which hurt…
Post: Testing FusionIO: strict_sync is too strict...
June 15, 2009 By 8 Comments
… kernel, so I was decided to test it in strict_sync mode. As I understand FusionIO in default mode, like Intel… internal memory, not to final media. And FusionIO has “strict_sync” mode to guarantee fsync is trustworthy. So let’s benchmark… benchmark on 100W (9GB data) with 3GB buffer_pool in O_DIRECT access. The raw number are here and graph is . Results…
Post: Disaster: LVM Performance in Snapshot Mode
February 5, 2009 By 55 Comments
… compared to run with no snapshot. NO O_DIRECT RUNS As you might know O_DIRECT often executes quite special path in Linux kernel so I did couple of other runs. First run syncing after each request instead of O_DIRECT /tmp/sysbench –test=fileio –num-threads=1…
Comment: MySQL 5.6.7-RC in tpcc-mysql benchmark
October 10, 2012 By 22 Comments
… in the following way: lock, write(), unlock, fsync() — so, if O_DIRECT is used, you’re keeping the “lock” time longer than…, I’ve advised to have a “pre-fetch” here rather O_DIRECT, but it was to short to implement the final REDO… stable, as the server will be in loop with short sync flushes.. Rgds, -Dimitri
Post: Disaster: MySQL 5.5 Flushing
September 18, 2011 By 27 Comments
… innodb_flush_log_at_trx_commit = 2 innodb_flush_method = O_DIRECT innodb_log_buffer_size = 16M innodb_buffer_pool_size = 52G… that stall we see is related to InnoDB flushing and “sync” state. Vanilla MySQL does not provide much diagnostic there, but… ). That is checkpoint age exceeds 75% sync mark, that is signal that InnoDB performs in “sync” flushing mode. So math formula for…
