On 7/8/2010 3:18 PM, Timothy.Noonan@emc.com wrote:
> How does the linux machine know that there is a BBU installed and to
> change its behavior or change the behavior of Postgres? I am
> experiencing performance issues, not with searching but more with IO.
>
It doesn't change its behavior at all. It's in the business of writing
stuff to a file and waiting until that stuff has been put on the disk
(it wants a durable write). What the write buffer/cache does is to
inform the OS, and hence PG, that the write has been done when in fact
it hasn't (yet). So the change in behavior is only to the extent that
the application doesn't spend as much time waiting.