Date: Tue, 27 Jun 2006 15:16:50 +0800 From: "leo huang" <leo.huang.list@gmail.com> To: "Eric Anderson" <anderson@centtech.com> Cc: freebsd-performance@freebsd.org Subject: Re: Is the fsync() fake on FreeBSD6.1? Message-ID: <14a4a8480606270016i1cadf037ue4818ccfecc22265@mail.gmail.com> In-Reply-To: <44A09EE7.1030405@centtech.com> References: <14a4a8480606261918q39b51f7bkd69958c5a7b05021@mail.gmail.com> <44A09EE7.1030405@centtech.com>
next in thread | previous in thread | raw e-mail | index | archive | help
Thanks Eric, Greg and Joseph. I will get more information from freebsd-fs@freebsd.org. 2006/6/27, Eric Anderson <anderson@centtech.com>: > leo huang wrote: > > Hi, > > > > I benchmarked MySQL 4.1.18 on FreeBSD 6.1 and Debian 3.1 using Super Smack > > 1.3 some days ago. > > > > The benchmark table is > > CREATE TABLE `Account` ( > > `aid` int(11) NOT NULL auto_increment, > > `name` char(20) NOT NULL default '', > > `flag` int(11) NOT NULL default '0', > > `uidcount` int(11) NOT NULL default '0', > > `balance` int(11) NOT NULL default '0', > > `point` int(11) NOT NULL default '0', > > `blocktm` int(11) NOT NULL default '0', > > `ipnum` int(10) unsigned default NULL, > > `newdate` datetime default NULL, > > PRIMARY KEY (`aid`), > > UNIQUE KEY `name` (`name`) > > ) ENGINE=InnoDB DEFAULT CHARSET=latin1; > > > > And it has 10,000,000 rows. > > > > The SQL statement is > > update Account set balance= balance + 1 where aid=?; > > > > The result is followed: > > OS Clients Result(queries per second) TPS(got > > from iostat) > > FreeBSD6.1 50 516.1 > > about 2000 > > Debian3.1 50 49.8 > > about 200 > > > > The result surprise me. The MySQL Performance on FreeBSD6.1 is about 10 > > times of on Debian3.1,and the output of iostat also shows it. > > > > I know that MySQL uses fsync() to flush both the data and log files at > > default when using innodb engine( > > http://dev.mysql.com/doc/refman/4.1/en/innodb-parameters.html). Our > > evaluating computer only has a 10000RPM SCSI hard disk. I think it can do > > about 200 sequential fsync() calls per second if the fsync() is real. > > > > Is the fsync() on FreeBSD6.1 fake? I mean than the data is only written to > > the drives memory and so can be lost if power goes down. And how I can > > confirm this? > > > > If the fsync() is fake, how can I get the real fsync? > > > > Any comment is welcome! > > > > PS: > > 1. Our evaluating computer is DELL PowerEdge 1650?Its hardware > > configuration > > is followed: > > CPU: 2 * Intel Pentium III 1.33GHz 512KB Level 2 Cache(smp) > > Memory: 1024MB ECC SDRAM > > HD: SEAGATE ST336706LC(36GB Ultra160 SCSI 10000RPM) > > NIC : Intel(R) PRO/1000 Network Connection > > > > 2. Some important parameters in MySQL configuration file are here: > > log-bin > > sync_binlog=1 > > innodb_safe_binlog > > innodb_buffer_pool_size = 384M > > innodb_additional_mem_pool_size = 20M > > innodb_log_file_size = 100M > > innodb_log_buffer_size = 8M > > innodb_flush_log_at_trx_commit = 1 > > innodb_lock_wait_timeout = 50 > > > Hi Leo, > > I think we've all received this message twice now, however if you are > resending because you didn't get any responses, it's probably because > most people on this list are here to discuss performance, and while this > is related, it is really a filesystem question, and so many people here > just won't know the answer for you. You might get a better response on > the freebsd-fs@ list. > > Anyway, there are a lot of variables here, but it could be softupdates. > Have you tried turning softupdates off on the filesystem you are > running this on, and/or enabling the 'sync' option to the filesystem? > > Also, you didn't mention anything about which filesystems these were > using on both occasions. > > Eric > > > -- > ------------------------------------------------------------------------ > Eric Anderson Sr. Systems Administrator Centaur Technology > Anything that works is better than anything that doesn't. > ------------------------------------------------------------------------ >
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?14a4a8480606270016i1cadf037ue4818ccfecc22265>