On Sun, Nov 14, 2010 at 8:34 PM, Evan D. Hoffman <evandhoffman@xxxxxxxxx> wrote: > I'm planning to migrate our pg db to a new machine in the next couple > of weeks. The current DB has 32 GB memory; the new one will have 96 > GB. It's going to be Postgres 8.2.x (we're planning to upgrade to 8.4 > as part of another project) running on CentOS 5.4 or 5.5. I know the > old rule of thumb that your swap partition/disk should be equal to the > physical memory, but when dealing with memory sizes greater than ~16 > GB that starts to seem strange to me; and now with 96 GB of physical > memory I'm starting to wonder if I'd be better off forgoing swap > altogether for the new database. My servers were setup with something like 16G of swap on a machine with 128G ram. After runnig for about a month of heavy work, kswapd decided to start thrashing the system for no apparent reason, and would not stop. The fix was sudo swapoff -a. As soon as kswapd had swapped everything back in the server returned to normal. Now, swapoff -a is the last line in my /etc/rc.local on both machines. Running Ubuntu 10.04 64 bit btw. Note that at the time of this happening I had 90+G of kernel cache, and nothing NEEDED to be swapped out. the linux kernel, and virtual memory, with a machine with lots of memory, has some rather odd behaviour, and I don't really need swap on these machines. -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
