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For the curious (I was): * vm.swappiness = 0 The kernel will swap only to avoid an out of memory condition, when free memory will be below vm.min_free_kbytes l

by gregmac 10y ago

For the curious (I was): * vm.swappiness = 0 The kernel will swap only to avoid an out of memory condition, when free memory will be below vm.min_free_kbytes limit. * vm.swappiness = 1 Minimum amount of swapping without disabling it entirely. * vm.swappiness = 60 The default value. * vm.swappiness = 100 The kernel will swap aggressively. https://en.wikipedia.org/wiki/Swappiness https://en.wikipedia.org/wiki/Swappiness

Jedd 10y ago
> vm.swappiness = 0 The kernel will swap only to avoid an out of memory condition, when free memory will be below vm.min_free_kbytes limit. This is not the case. It used to be the case, but changed in kernel version 3.5-rc1 (2012 ish) There was a discussion about this on HN a few weeks ago: https://news.ycombinator.com/item?id=13511086 https://news.ycombinator.com/item?id=13511086 And there's a blog post on the percona website about how this rather bizarre change bit them: https://www.percona.com/blog/2014/04/28/oom-relation-vm-swappiness0-new-kernel/ https://www.percona.com/blog/2014/04/28/oom-relation-vm-swap... I call it bizarre because (as I wrote in that other HN thread) a) it changed the behaviour of lots of production systems in a surprising way, and b) if you want to ensure your processes never swap you already had the option to not have a swap file or partition.