Thanks for the detailed reply. Will try it out. On Sun, Feb 13, 2011 at 5:08 AM, Hugh Williams <[email protected]>wrote:
> Hi Abhi, > > Although O_DIRECT can be enabled for those OS'es that support it, testing > performed by development has shown no evidence of performance improvements > hosting large databases on any of the OS;es tested on. > > If testing on Linux their is a kernel configuration called "swappiness" > that controls how much the kernel favors swap over RAM: > > > http://www.linuxvox.com/2009/10/what-is-the-linux-kernel-parameter-vm-swappiness/ > > When hosting large datasets, as you are, it is recommended this parameter > be changed from is default value of 60 to something like 10, which is what > we use on the dbpedia and lod etc services we host, to reduce that amount of > swapping that takes please on the server. > > Note: > > 1. The swappiness setting resides in the file "/proc/sys/vm/swappiness" > 2. The command "/sbin/sysctl vm.swappiness" can be used to view its setting > > 3. The command "/sbin/sysctl -w vm.swappiness=10" can be used to change its > value > 4. Adding the "vm.swappiness = 10" to the file "/etc/sysctl.conf" will > force the value to be set at machine boot time. > > Let me know if his helps. > > Best Regards > Hugh Williams > Professional Services > OpenLink Software > Web: http://www.openlinksw.com > Support: http://support.openlinksw.com > Forums: http://boards.openlinksw.com/support > Twitter: http://twitter.com/OpenLink > > On 9 Feb 2011, at 06:18, Abhi wrote: > > Sorry for the delayed response, I am not very clear as to how o_direct > works. If I am not mistaken, I think it has to do something with OS page > caching, where virtuoso also caches data and OS also caches data in the form > of page files and this double caching is avoided with the o_direct > parameter. I maybe completely wrong here. If I am please correct me. > > I want to test the performance benefits of using this parameter as we are > expecting load sizes of billions of triples in our store. All I know is that > o_direct param in the ini file enables this and this is OS dependent. But, > is there any document out there which says which OSes support this parameter > and are there any changes that needs to be done in Linux kernal(while > compiling the Kernal or some config file) to enable this? Any document on > this(Unix related or Virtuosos related) will help me in better understanding > what is going on behind the scene. > > On Sun, Jan 23, 2011 at 7:41 AM, Hugh Williams > <[email protected]>wrote: > >> Hi Abhi, >> >> Is this a Unix or Virtuoso question ie do you want to know what OS'es >> support it or on what OS'es Virtuoso supports it ? >> >> Best Regards >> Hugh Williams >> Professional Services >> OpenLink Software >> Web: http://www.openlinksw.com >> Support: http://support.openlinksw.com >> Forums: http://boards.openlinksw.com/support >> Twitter: http://twitter.com/OpenLink >> >> On 21 Jan 2011, at 03:11, Abhi wrote: >> >> > Is there a list of OSes that support the O_DIRECT param or does anybody >> know how do i find whether a particular OS supports it? >> > >> > -- >> > Cheers, >> > Abhi >> > >> ------------------------------------------------------------------------------ >> > Special Offer-- Download ArcSight Logger for FREE (a $49 USD value)! >> > Finally, a world-class log management solution at an even better >> price-free! >> > Download using promo code Free_Logger_4_Dev2Dev. Offer expires >> > February 28th, so secure your free ArcSight Logger TODAY! >> > >> http://p.sf.net/sfu/arcsight-sfd2d_______________________________________________ >> > Virtuoso-users mailing list >> > [email protected] >> > https://lists.sourceforge.net/lists/listinfo/virtuoso-users >> >> > > > -- > Cheers, > Abhi > ------------------------------------------------------------------------------ > The ultimate all-in-one performance toolkit: Intel(R) Parallel Studio XE: > Pinpoint memory and threading errors before they happen. > Find and fix more than 250 security defects in the development cycle. > Locate bottlenecks in serial and parallel code that limit performance. > > http://p.sf.net/sfu/intel-dev2devfeb_______________________________________________ > > Virtuoso-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/virtuoso-users > > > -- Cheers, Abhi
