Hi,

At February 20, 2005, 06:59, Steffen Heil wrote:

> Hi

>> Windows would cache the data in memory what ever you
>> did. ... CODEBASE
>> addressed a number of the problems in the same way as 'Forced
>> Write', by bypassing windows, and pushing each write direct
>> to the disk.
>> The whole problem is simply windows was never designed to be
>> a server operating system, and until it addresses that
>> problem, we need to prevent it from getting in the way by
>> 'Forced Write' of data to the disk, or using a 'safer' OS,
>> which actually writes the cache with some level of urgency ;)

> Ok, my fault. I assumes "Forced Writes" to be enabled.
> Not enabling this is scaring for any firebird database on any system...

> However, if forced writes is turned off, then it is absolutely correct for
> windows to cache writes...

> So, where is the problem?

Linux will write it's cache to disk once-in-awhile.

Windows will only write the cache to disk once the application closes
the file handle. So, basically, if you have an application that stays
connected to the Firebird database for 1 month continuously, no data
is written to disk for that period of time. Well come to think of it,
Windows will write the cache to disk, to it's own paging file, not the
database file.

But, with Firebird 1.5 (Forced Writes=OFF), it is now possible to
tweak when Windows cache is supposed to be written to disk, it can be
set to a certain time interval and/or number of transactions. It uses
a disk write method that bypasses the Windows disk cache, and will
wait for a confirmation that the data has been written.

--
Best regards,
Daniel Rail
Senior System Engineer
ACCRA Group Inc. (www.accra.ca)
ACCRA Med Software Inc. (www.filopto.com)