On 1.2.2011, at 5.11, Stan Hoeppner wrote:
This depends on how the dev does his syncs. If done intelligently, XFS performance won't suffer. In fact, the preferred write method to XFS for high performance applications is using O_DIRECT. Using O_DIRECT, correctly, with XFS, actually _increases_ write performance versus going through the buffer cache. So you get the best of both worlds: higher performance and data guaranteed on disk.
O_DIRECT is completely useless for just about every application there is. It was written for Oracle, and I doubt there are many applications outside (SQL) databases that use it at all.
Read Ted's article I linked. I didn't misquote him. The simple point he was making is that unless devs specifically use fsync or other calls to guarantee their data is on disk, they will suffer data loss with any modern journaling filesystem when the power goes out or the system crashes. You seem to be assuming all devs use fsync. Apparently this is far from reality.
Ted also thinks everyone should be using SQL(ite) database rather than filesystems directly. Many people don't agree.