HAMMER Update 12-July-2008

[Matthew Dillon]

    Here's another update!

    We're still on track for the release.  HAMMER Development will continue
    in HEAD next week after the branch, and then get synced to 2.0 for
    the release.  In the last few days:

    * The mirroring support was finished this week and is undergoing
      testing.   This was the last big-ticket item on my list so yip yip!

    * Miscellanious performance, memory, buffer cache deadlocks, and
      undo fifo exhaustion issues have been fixed.  Random write
      performance has significantly improved.


    Currently there are two known bugs:

    * Filesystem full handling needs more work.

    * There are some races between either the pruner or the reblocker,
      and front-end access (such as a buildworld) which can result in
      bad data that need to be addressed.  I'm identifying which and
      tracking it down.

      It's probably the reblocker, related to the fact that it is
      manipulating the B-Tree directly and not going through the
      related inode/vnode, so there is minimal locking between the
      reblocker and the front-end and possibly some buffer cache
      aliasing.

					-Matt
					Matthew Dillon 
					<dillon at backplane.com>