On Tue, May 5, 2009 at 11:15 AM, PFC <lists@xxxxxxxxxx> wrote: > >> An octocore server with 32GB of ram, running postgresql 8.3.6 >> Running only postgresql, slony-I and pgbouncer. >> >> Just for testing purpose, i tried a setting with 26GB of shared_buffer. >> >> I quickly noticed that the performances wasn't very good and the >> server started to swap slowly but surely. >> (but still up to 2000query/second as reported by pgfouine) >> >> It used all the 2GB of swap. >> I removed the server from production, added 10GB of swap and left it >> for the weekend with only slony and postgresql up to keep it in sync >> with the master database. >> >> This morning i found that the whole 12GB of swap were used : > > Hm, do you really need swap with 32Gb of RAM ? > One could argue "yes but swap is useful to avoid out of memory > errors". > But if a loaded server starts to swap a lot, it is as good as dead > anyway... Not really, but we have it. I tried with swappinness set to 0 and ... it swaps ! I'm back to 4GB of shared_buffer :) I'll try various setting, maybe 16GB, etc ... But my goal was to avoid OS filesystem cache and usage of shared_buffer instead : FAIL. -- F4FQM Kerunix Flan Laurent Laborde -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
