LARGE single-system Cyrus installs?

Rob Banz rob at
Tue Nov 20 14:02:11 EST 2007

We went through a similar discussion last year in OpenAFS land, and  
came the same conclusion -- basically, if your filesystem is  
reasonably reliable (such as ZFS is), and you can trust your  
underlying storage not to lose transactions that are in-cache during a  
'bad event', the added benefit of fsync() may be less than its  
performance cost.


On Nov 20, 2007, at 08:32, Michael R. Gettes wrote:

> I am wondering about the use of fsync() on journal'd file systems
> as described below.  Shouldn't there be much less use of (or very
> little use) of fsync() on these types of systems?  Let the journal
> layer due its job and not force it within cyrus?  This would likely
> save a lot of system overhead.  It makes sense to use on non-journal'd
> fs.  I also wonder whether modern arrays even respect FULLFSYNC
> given their more complex nature and I/O scheduling algorithms.  It
> may be time that fsync() (and fcntl(F_FULLFSYNC)) have become moot
> since there is likely little way to influence, in an effective
> targeted way, I/O behavior in complex environments these days.

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