HAMMER update 05-May-2008

[Matthew Dillon <dillon@xxxxxxxxxxxxxxxxxxxx>]

    I am now working on the filesystem full handling.   Everything else is
    working and appears to be stable.

    Current issues:

    * There may be a few undo cases where recovery-after-crash is
      unsuccessful, or results in an assertion later on.  I found
      a big issue with the kernel itself trying to sync the buffers
      and I whacked that (the last thing HAMMER wants is for the kernel
      to sync its buffers!).  I am continuing to test by intentionally
      crashing the system both under a vkernel and on real test boxes.

    * Reading and writing are not optimized well yet.  For reading the issue
      is a lack of clustering and read-ahead support (yet).  For writing
      the issue is due to the way buffers are staged out to the backend.

      Both issues are fairly straight forward, but they aren't high
      priority at the moment.

    * The filesystem full handling isn't in yet.  That is next on my list.

    I have begun testing HAMMER on real hardware.  My backup machine is now
    running a 700GB HAMMER filesystem.  I expect more issues will work their
    way out of the woodwork but right now things are looking *very* good.

					-Matt
					Matthew Dillon 
					<dillon@backplane.com>