Hi Chris I read something about the dangers to use vm.drop_caches so I was in doubt. During the weekend our users didn't stress the system, the number of changelog went down to ca. 0 and for this reason I cannot give you any useful feedback about last settings. I took advantage of the fact thee machine was empty to perform a "rbh-config optimize_db" which gave me some benefits too (now the read speed varies between 2500 to 10000 record/sec). Anyway I'm waiting users start stressing the machine again to see what it will happen. I will let you know.
regards Carmelo On Mon, 2015-05-11 at 11:06 -0400, Chris Hunter wrote: > Hi Carmelo, > > Glad you to hear you are making progress. > vm.drop_caches is disruptive, it will likely dump the cache for your > local filesystem, mysql buffer, etc. Too aggressive vfs_cache_pressure > values can cause similar problems. > I found running the lru_size=clear command hourly gave about the same > results as setting lru_max_age to one hour, YMMV. > > regards, > chris hunter > yale hpc group > > On 05/08/2015 10:47 AM, Carmelo Ponti (CSCS) wrote: > > Chris > > > > On Thu, 2015-05-07 at 11:56 -0400, Chris Hunter wrote: > >> Hi Carmelo, > >> > >> What I found is once the local vfs cache is full, robinhood GET_INFO_FS > >> speed drops. You can monitor (via /proc/meminfo) buffer, cached & slab > >> memory usage when starting robinhood, you will see these values reach > >> threshold after a time. Once this state is reached, parameters > >> lru_max_age and vfs_cache_pressure are important. > > > > I see your point now. I increased vfs_cache_pressure to 125 and I > > monitoring buffer, cached & slab as you suggested. I will check on > > Monday and let you know. > > > >> You can also "flush" lustre cached ldlm locks by echoing "clear" to > >> lru_size parameter. > > > > I scheduled this every hour in cron. > > In addition on > > https://urldefense.proofpoint.com/v2/url?u=https-3A__www.kernel.org_doc_Documentation_sysctl_vm.txt&d=AwICaQ&c=-dg2m7zWuuDZ0MUcV7Sdqw&r=d_G2h_sZYG4xtHMeKo8QgjDmOcMVdQvYgM-5Dri1AOY&m=2e-uiK2hYQaNO4gSQJmS-sbkcCSotxt3gGa7oYx5vds&s=j5zzS6pU4jPUsa4HvMfpFTrBqUXcffJvk08rLyK0sNg&e= > > I'm reading about /proc/sys/vm/drop_caches. Do you think it could help > > dropping slab objects and pagecache? (echo 3 > >> /proc/sys/vm/drop_caches). > > > > Carmelo > > -- ---------------------------------------------------------------------- Carmelo Ponti System Engineer CSCS Swiss Center for Scientific Computing Via Trevano 131 Email: [email protected] CH-6900 Lugano http://www.cscs.ch Phone: +41 91 610 82 15/Fax: +41 91 610 82 82 ---------------------------------------------------------------------- ------------------------------------------------------------------------------ One dashboard for servers and applications across Physical-Virtual-Cloud Widest out-of-the-box monitoring support with 50+ applications Performance metrics, stats and reports that give you Actionable Insights Deep dive visibility with transaction tracing using APM Insight. http://ad.doubleclick.net/ddm/clk/290420510;117567292;y _______________________________________________ robinhood-support mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/robinhood-support
