Maybe buy battery based raid card Em sáb, 7 de set de 2019 às 15:27, Jure Sah <dustwo...@gmail.com> escreveu:
> Hi, > > It would appear that on a typical webserver, the majority of disk i/o > belongs to the MariaDB database process. It would appear it's mostly > waiting on fsync(), which to my understanding is executed at least once > per commit. > > I understand that this is extensively researched in the documentation > and it has to do with the recovery of data in case of an unexpected > server reboot. > > The thing is, this has many performance issues because it caps database > performance at whatever the speed of the underlying physical storage is, > even if the changed data fits into the available RAM. It also results in > the circumstance where if anything is impacting performance of the > storage system on the server, this will break MariaDB and cause the > service to go offline (time out), even if there is sufficient RAM in the > machine to continue operating as normal from page cache. > > In a typical scenario you have a website which is writing things like > session and page cache data which expires within an hour and would be no > great loss if missing from a backup. Especially if the volume of the > missing data would be 30 seconds (kernel default for committing dirty > pages to disk) and mind you this setting is configurable. > > Temporary tables cannot be used in this case, because they are deleted > as soon as the session ends, which is too soon. > > Is there a different solution that could be used here? > > > I've also noticed in the documentation that the options to control fsync > usage are even more limited than in the MySQL server. They are also very > strongly argued against. Considering the point that InnoDB is considered > to be in an inconsistent state in any event, so long as the server is > not cleanly stopped, is there really justification for such strong > opposition here? > > Disabling fsync boosts performance of a typical MySQL server by > something like a factor of 3. > > LP, > Jure > > _______________________________________________ > Mailing list: https://launchpad.net/~maria-discuss > Post to : maria-discuss@lists.launchpad.net > Unsubscribe : https://launchpad.net/~maria-discuss > More help : https://help.launchpad.net/ListHelp > -- Roberto Spadim SPAEmpresarial - Software ERP/Scada Eng. Automação e Controle, Eng. Financeira
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