On 8/19/2015 4:17 PM, Leon Fauster wrote: > Am 19.08.2015 um 10:24 schrieb John Hodrien <J.H.Hodrien at leeds.ac.uk>: >> On Wed, 19 Aug 2015, Jatin Davey wrote: >> >>> Hi All >>> >>> We use CentOS 6.6 for our application. I have profiled the application and find that we have a heavy requirement in terms of Disk writes. On an average when our application operates at a certain load i can observe that the disk writes / second is around 2 Mbps (Average). >> Initial thought is, do you really care? 2Mbps is peanuts, so personally I'd >> leave everything at the defaults. There's really no need to optimise >> everything. >> >> Obviously the exact type of writes is important (lots of small writes written >> and flushed vs fewer big unsynced writes), so you'd want to poke it with >> iostat to see what kind of writes you're talking about. > > > to address this we use (sysctl) > > vm.dirty_expire_centisecs > vm.dirty_writeback_centisecs > > furthermore check the fs alignment with > the underlying disk ... > > -- > LF [Jatin] These options deal with "caching" the writes. Correct me if i am wrong. If it is indeed dealing with caching then i think it will not help because the application workload generates a lot of data that is always new. The application logic continously generates new data to be written to disk. > > > > > > _______________________________________________ > CentOS mailing list > CentOS at centos.org > http://lists.centos.org/mailman/listinfo/centos > Thanks Jatin