can you explain why "20480 pages (80 Mo) is a typo" ?
Witch value or rule do you suggest to apply ?

the typical machine will have 2 to 4 core cpu xeon 3ghz.

--- In firebird-support@yahoogroups.com, "Adam" <s3057043@...> wrote:
>
> --- In firebird-support@yahoogroups.com, "mohamed.banaouas"
> <mohamed.banaouas@> wrote:
> >
> > thanks a lot for your feedback.
> > On SuperServer, I usually set DefaultDbCachePages=20480 corresponding
> > to 80 Mo ram. Application access to only one database. There is up to
> > 100 concurrent connexions.
>
> I hope that 20480 is a typo ;)
>
> > The server has 4 Go RAM.
> > Should I keep the same value on classic ?
>
> No. The values are per engine instance, and Classic server has one
> engine instance per connection whereas Superserver has a single shared
> engine instance. You can see this reflected in the default values for
> the cache settings in firebird.conf. Superserver can afford a higher
> value because you know there is only one engine running.
>
> You haven't answered the most important question still. I have already
> mentioned that the 'big win' of classic is that it can better use
> multiple CPU cores. The OS can allocate a different core to each
> fb_inet_server.exe process (for which you have one per connection +
> one additional). Most other performance aspects are a close lose for
> Classic. So how many cores does your server have? Quad core (or
> higher) generally favours Classic. Single core generally favours
> Superserver. Dual core is 50:50. In any case, you should configure a
> test environment to ensure you are using the overall optimal engine.
>
> As a 32-bit process, Superserver is limited to 2GB RAM. Classic is
> limited to 2GB per connection.
>
> Adam
>