Manipulating disk cache (buf) settings
gurney_j at resnet.uoregon.edu
Mon May 23 16:30:04 PDT 2005
Vivek Khera wrote this message on Mon, May 23, 2005 at 17:17 -0400:
> On May 23, 2005, at 1:44 PM, John-Mark Gurney wrote:
> >This is incorrect... FreeBSD merged the vm and buf systems a while
> >so all of memory is used as a disk cache.. The buf cache is still
> >for filesystem meta data (and for pending writes of files, but
> >those buf's
> >reference the original page, not local storage)...
> Cool... So what would you recommend telling an application like
> Postgres what the cache size is? All of RAM? That seems unlikely
> given much of the ram is used for other things. Is there no upper
> bound in how much RAM will be used for the cache?
I'm not familar host Postgres uses the cache number to change it's
behavior, but I would say choose a responable amount of memory that
you expect to regularly have available on the system... If you are
only using it for db, and a few other small processes, 512meg less
than ram is probably reasonable...
The other way is to try a few different values and see how it impacts
John-Mark Gurney Voice: +1 415 225 5579
"All that I will do, has been done, All that I have, has not."
More information about the freebsd-amd64