Hi, On 2020-04-29 10:50:54 +0200, Laurenz Albe wrote: > On Wed, 2020-04-29 at 08:54 +0200, Marc Rechté wrote: > > I am trying to figure out the recommended settings for a PG dedicated > > machine regarding NUMA. > > > > I assume that the shared buffers are using Huge Phages only. Please > > correct if I am wrong: > > > > 1) postgres is started with numactl --interleave=all, in order to spread > > memory pages evenly on nodes. > > 2) wm.swappiness is left to the default 60 value, because Huge Pages > > never swap, and we wish the idle backend to be swapped out if necessary. > > 3) vm.zone_reclaim_mode = 0. I am not sure it is the right choice. > > 4) kernel.numa_balancing = 1. Only if it is confirmed that it will not > > affect postgres, because started with the interleave policy. > > I am not the top expert on this, but as far as I can tell: > > - Disabling NUMA is good if you want to run a single database cluster > on the machine that should use all resources. > > If you want to run several clusters that share the resources, leaving > NUMA support enabled might be the better thing to do. > > - If you can, disable NUMA in the BIOS, on as low a level as possible. I am doubtful that that's generally going to be beneficial. I think the strategy of starting postgres with interleave is probably a better answer. - Andres
