Michael,

> We have just this night moved an 80Gb DB from one server to another this
> night.
>
> And today performance of the DB is slow! So slow it is almost unusable.
>
> Before we switch back I would like some suggestions, which I might not have
> considered. But first background.
>
>
> FIREBIRD:
> Firebird 2.1 64 bit
>
> OLD SERVER:
> Some linux version (not quite sure which).
> 8 Gb RAM
>
> NEW SERVER:
> Windows Server 2008
> 8 Gb RAM
> Firebird uses on average 0-25% CPU. Nothing else seems to take any CPU.
> There should be no AntiVirus software on this new server

Have a look at the fixes for known page cache issues with Windows 64 bit servers.

The basic issues is that, by default wants to cache all disk pages and with a 64 bit OS it think it has a huge amount of RAM. So once all physical RAM has been consumed Windows starts to read/write to the disk page file, which causes an excessive amount of disk IO and thus slows the system.

There are published fixes for this issue.


Sean