> - when Firebird is ended abnormally (ie UDF problem...) with a
> database connected, it could corrupt it if forced writes is OFF ?

Yes.

Further if the physical server abends (power is lost for longer than UPS
can support) then a corruption can occur.

> - if you shutdown Firebird server normally, same problem or everything
> is properly closed ?

No. This should not be a problem, but it does depend on the OS.

Some OS (like Windows) can buffer writes independent of the application.

> and decrease of performance is 3x less always ?

Yes, but don't think of the performance as degraded, think of the
non-Forced Writes as DANGEROUS.

Nothing comes for free, better slow database writes then a database
which is corrupt!

Also, the Forced Write 'penalty' can be minimized by using good disk
controller *with* battery backed-up cache, which can allow you to enable
the "write-back" feature of the controller. (Write-back immediately
tells the OS that the disk write has occurred even though the controller
may still have the write in its cache).


Sean