That's true, but this is not for performance. If you run a large VM on linux, with swappiness at 60, the OS will steal your pages, cause you to swap, miss your deadlines, and crash your tserver. But only after letting you think everything is fine for an hour or so.
Another example: accumulo will now detect configurations where cache+memory-map > max memory. Before, it would work for a while, and then ... slow death by stop-the-world garbage collection. Better to detect it up-front an not have to sherlock it from log files. -Eric On Thu, Jun 7, 2012 at 9:31 PM, Jim Klucar <[email protected]> wrote: > I think that could be a slippery slope. We can't possibly support all > the Linux settings required for optimal performance on all > distributions. > > Sent from my iPhone > > On Jun 7, 2012, at 7:36 PM, David Medinets <[email protected]> > wrote: > > > I don't know the impact when this setting is too high. Apparently the > > default in Ubuntu is 60. I only noticed the warning because I was > > looking at log files randomly. I'm wondering if this check is > > important enough to be done when the shell starts and to display the > > error to the console at that time. > > > > This was the message: > > > > [server.Accumulo] WARN : System swappiness setting is greater than ten > > (60) which can cause time-sensitive operations to be delayed. > > Accumulo is time sensitive b > > ecause it needs to maintain distributed lock agreement. >
