On Thu, Feb 25, 2010 at 1:38 PM, Daniel Maher <[email protected]<dma%[email protected]> > wrote:
> Raghavendra G wrote: > >> Hi Daniel, >> >> Can you decrease the cache size in io-cache (say to 128MB)? If the files >> being served are bigger than this size, you can as well remove io-cache from >> configuration. Do let us know if this solves your issue. >> > > Some of the files that are generated during the test are under 128M, and > some are much larger - effectively, the test deals with larger and larger > sets of data as it runs its course. > > At your suggestion, i changed the io-cache size from the default setting > (as generated by the configurator) to 128M, and re-ran the test. The > results are now much more consistent with what would be expected : > > real 21m31.019s > real 21m30.932s > real 21m28.965s > real 21m26.095s > real 21m26.388s > real 21m29.377s > real 21m32.180s > real 21m26.600s > real 21m28.354s > (cut for brevity) > > However, at two points during the multi-day test run, something strange > happened. The time to completion dropped _dramatically_, and stayed there > for numerous iterations, before jumping back up again : > Mostly reads are being served from io-cache? > > real 21m27.806s > real 21m45.434s > real 14m41.468s > real 12m41.172s > real 12m39.779s > real 12m34.595s > real 12m42.223s > real 12m41.111s > (repeat 30 iterations) > real 12m40.185s > real 12m40.517s > real 13m25.394s > real 21m26.375s > real 21m28.476s > > I am forced to assume that something else on either the client or the > server nodes caused this behaviour, but i cannot imagine what. The nodes, > frankly, aren't doing anything else. Very strange. > > I am going to remove the io-cache entirely and see what, if any, effect > that has. > > > -- > Daniel Maher <dma+gluster AT witbe DOT net> > > > _______________________________________________ > Gluster-devel mailing list > [email protected] > http://lists.nongnu.org/mailman/listinfo/gluster-devel > -- Raghavendra G
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