[OpenAFS-devel] Patch to disable fsync()ing

[Robert Banz]

On Mar 16, 2007, at 12:38 PM, Rainer Toebbicke wrote:

> Derrick J Brashear wrote:
>> On Fri, 16 Mar 2007, Robert Banz wrote:
>>>
>>> The following patch adds the options "-nofsync" to the namei- 
>>> based fileserver and volserver, disabling fsync() operations.
>>>
>>> For the volserver, local tests have shown that this speeds up  
>>> volume moves significantly.
>> If it's like the one Rainer sent it also breaks things. Ask Harald  
>> Barth.
>
> Well, I seeing that it got dropped from CVS I checked with Harald  
> and he himself does not think so any longer. He must have had some  
> other problem. The necessity for syncs (except crashes) also  
> somehow contradicts POSIX to my understanding.
>
> We run with a variant of mine which nevertheless does syncs in a  
> separate thread for safety since years now and could frankly not do  
> without. However better programmers than me aren't rare and  
> delaying the syncs is not a very tricky task.

My theory with the fsync thing, is that the OS is going to flush  
dirty stuff to disk anyhow.  So, I figure to just let it do that and  
not try to implement a bunch of code to flush'm when something else  
should be doing it for me.

-rob