From: Rob Banz (no email)
Date: Tue Nov 20 2007 - 14:02:11 EST
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.
-rob
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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