On Sat, 2009-12-19 at 09:08 +0100, Arjan van de Ven wrote: > On Fri, 18 Dec 2009 16:20:11 -0500 > Steve Rago <sar@xxxxxxxxxxxx> wrote: > > > > > I don't disagree, but "that's not what we do" hardly provides insight > > into making the judgment call. In this case, the variety of > > combinations of NFS server speed, NFS client speed, transmission link > > speed, client memory size, and server memory size argues for a tunable > > parameter, because one value probably won't work well in all > > combinations. Making it change dynamically based on these parameters > > is more complicated than these circumstances call for, IMHO. > > > if you as the expert do not know how to tune this... how is a sysadmin > supposed to know better? > I did not say I didn't know how to tune it. I said you put the tunable parameter in as a compromise to doing something far more complex. You then adjust the value according to various workloads (in this case, iozone or something that more closely resembles your application). The same way I figure out how man NFSD processes to configure; the same way I figure out acceptable values for dirty_ratio and dirty_background_ratio. The code has a reasonably conservative default, and people can adjust it if their circumstances differ such that the default doesn't provide acceptable results. Steve -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
