[ZODB-Dev] Re: Use of fsync in FileStorage

[Christian Robottom Reis]

On Fri, Jul 30, 2004 at 01:33:40AM -0400, Tim Peters wrote:
> System.  Bottom lines on that were:
> 
>     436.964 txn/sec  2 fsync
>     549.359 txn/sec  1 fsync
>     764.286 txn/sec  0 fsync
> 
> So that was an instance of the "< 2X difference no matter what" pattern.

I'm sure I can add more fsyncs to make it degrade more intensely if we
want to make sure it fits to one of these performance patterns we've
uncovered <wink>.

Today one of our developers moved a .fs file while the ZEO was running
and then did some sort of evil thing to it. He was then surprised when
running the ZEO again provided us with a database corruption exception.

It's interesting to note that in over a year of production use this was
the first time I encountered this sort of problem -- and it had me going
"Tim will love this" until I realized what he had done.

Take care,
--
Christian Robottom Reis | http://async.com.br/~kiko/ | [+55 16] 3361 2331