On Fri, Mar 16, 2012 at 11:14:04AM -0700, Alexandre Depoutovitch wrote: > Hello, > I am trying to do random sector aligned writes to an NFS mounted disk. The > performance is order of magnitude worse than 4K (file system block size) > aligned I/O. > The reason is that NFS demon (Linux kernel 2.6.32) on the server side > always does buffered I/O, which behaves poorly for block unaligned > requests. > Is there a way to tell NFS daemon to use direct I/O? No. > If not, is it an implementation limitation or there is a fundamental > problem with using direct I/O in NFS server? I'm shamefully ignorant of Direct IO.... If we supported Direct IO, are there heuristics that would let the server figure out on its own when it helped and when it didn't? Or would the administrator be stuck trying to figure that out? Is Direct IO possible from kernel buffers these days? Are there alignment restrictions? --b. -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
