2007-05-07: Release version 2.15 ("fsck/drain/rebalance")

        * minor bug fixes and enhancements for MultipleHosts replication
          policy.  bunch of corner cases now checked with new tests.
          now easy to write more replication policy tests in future.

        * replication policies can now return "desperate" requests,
          signalling that a replication reassessment should be
          enqueued for the future, to see if things could be improved.
          (that part's not currently implemented, but the real feature
           and motivation is that the rebalancer now won't delete a
           DevFID if it results in a desperate move, only an ideal move. )

        * replication policies now can optionally return a new return
          value of the (new) type MogileFS::ReplicationRequest, which
          has pretty accessor names, can suggest multiple places,
          can indicate non-ideal emergency replication decisions.
          old plugins' return values will be transparently upgraded
          to the equivalent new return value objects.

        * adding new device state: "drain".  it's a hybrid of "dead"
          (in that files are migrated off it) and "readonly", it that
          it still serves traffic... it just doesn't get new files.
          this also introduces the new object-oriented DeviceState class,
          and device_state($name) utility function to get the DeviceState
          singleton by name

        * internal code cleanup.  notably, kill the old & nasty legacy
          'find_deviceid' function which was ridiculously long and hairy.
          the two callers are now more readable with sorts/greps/etc.

        * make mogstored's devN/usage writing process (DiskUsage) be less
          racy with the mogilefsd monitoring code... don't open file for
          write... open read/write, then in one write system call, write
          the entire file, with newline padding at end to cover old data,
          then truncate it if necessary.  should remove harmless (but scary)
          error messages previously reported by the mogilefsd monitor
          about zero-length usage files.

        * new protocol commands to list/set (certain) server settings,
          with value sanity checking (see MogileFS::Config for which
          are settable, and with what values).  needed for "enable_rebalance".
          was partially enabled before for slave settings.  also needed
          for memcached support before, which was never possible to
          set with mogadm, only with db tweaking.

        * make mogilefsd fsck use new mogstored fid_sizes command, to
          do bulk stats.  speeds up fscks a ton.

        * be robust against system clocks that go backwards between
          gettimeofday calls:
          http://lists.danga.com/pipermail/mogilefs/2007-April/000897.html

        * Put gearman server in mogstored process, add worker
          'mogstored-fidsizes' which runs as subprocess of mogstored. Add
          side-channel command 'fid_sizes' which allows us to quickly enumerate
          and get sizes for files across entire devices on a storage node.

        * remove all code like $state eq "readonly", $state=~ /^dead|down$/
          and instead convert it into specific questions on policy/traits
          of given state, like $dev->should_put_new_files_on, or
          $dev->should_drain_files_off.  see MogileFS::DeviceState,
          objects of which are accessed via $dev->dstate, or new
          MogileFS::Util device_state($name) wrapper.

        * start of rebalance support.  (where replication workers, in their
          idle time, can rearrange files to even out disk space and/or IO
          activity on storage nodes... policy isn't hard-coded, and is
          in fact currently random)

        * lighttpd support in both mogilefsd and mogstored.  passes test
          suite with environment MOGSTORED_SERVER_TYPE=lighttpd set now.

        * abstract out the HTTP server support in mogstored, so
          mogstored isn't just a perlbal wrapper, but an anything
          wrapper. (in particular, lighttpd and apache)  mogstored still
          exists for all its other misc admin/monitoring functions,
          but can then manage/configure apache/lighttpd child process(es).
          so far they're just stubbed out.

        * split mogstored into separate files per class, rather than one
          large script.

2007-04-24: Release version 2.10

        * bug from earlier refactoring:  changing some 'next' to 'return'
          in MogileFS::Device's create_directory method.  (thanks to
          Justin Huff <jjhuff@mspin.net>)

        * make sure mogdbsetup doesn't upgrade an existing table (with
          potentially lot of data) from MyISAM to InnoDB.  just warn.
          only new tables should become InnoDB on creation.  also,
          detect InnoDB even on old MySQL 4.0.x, not just 4.1/5.0.

        * make fsck faster by reducing number of db queries (both
          reads and writes), though more unrelated fastness remains to
          be done.

        * make fsck_status faster (keep summary stats of evcode counts,
          rather than doing a full GROUP BY query all the time)

2007-04-20: Release version 2.09

        * filesystem checker (Fsck worker).  off by default, unless
          it's enabled via protocol.  Control/monitor it with mogadm
          in MogileFS-Utils 2.08, which needs MogileFS::Client 1.06.

        * replication speed-up on configurations with only 1 host.
          (replication would randomly have no suggestions before, when
           there was only 1 target host, so replication would be rescheduled
           until the future, when random returned a different device on
           that host)

2007-04-17: Release version 2.08

        * (no runtime-visible changes from 2.07)

        * mogilefsd: remove incomplete "Checker" worker, replace with
          incomplete "Fsck" worker.

        * test cleanup/robustness improvements.  properly skips testing when
          testin deps not found.  but searches harder for them now, too.
          tests run under "make disttest".

        * packaging cleanups, released using ShipIt.


2007-03/04:

        * mogilefsd: Split Plugin::MetaData and Plugin::FilePaths into their own distributions.

        * mogilefsd: Fix mogdbsetup to not ask empty questions.

        * mogilefsd: command line/config file support for listening on specific IPs, also
           support for listening on multiple IPs/ports

2007-03-19:
        * mogstored: use XS HTTPHeaders by default, unless disabled with environment variable

        * mogilefsd: memcache support for get_paths (see doc/memcache-support.txt)

2007-03-16:
        * mogstored: make child processes be exec'ed (as as their own scripts, not inhertting
          Perlbal, Linux::AIO/IO::AIO, etc baggage).  so they don't own listening
          sockets, pipes to child workers, signal handlers, etc.  just a lot
          cleaner now, and SIGTERM, SIGINT properly shut everything down now,
          both in foreground and as daemon

2007-03-15:
        * mogstored: this changelog is totally neglected.  :/  see svn log.

        * mogstored: make perlbal's "shutdown graceful" work, by not doing
          sidechannel accepting ourselves (which never hung up),
          but subclass Perlbal's TCPListener class, which does it
          all correctly.

2006-12/2007-01:  (2.00_05)
        * mogilefsd: everything converted to OO API internally.  old internal APIs removed.

        * mogilefsd: be database-agnostic.  Currently only works with MySQL (and
           SQLite as a joke/demo), but Pg/Oracle coming in the future.

        * mogilefsd: built-in I/O activity monitoring between mogstored/mogilefsd Monitor
           now.

        * mogilefsd: much improved internal communication between worker processes

        * mogilefsd: start of better docs

2006-12-28
        * mogilefsd: pidfile support (Radu Greab <radu@yx.ro>)

2006-12-28
2006-12-27
        * mogilefsd: remove all old internal APIs, update everything to use new OO APIs,
           expanding OO APIs where necessary (lots of places).  so much more
           beautifully hackable now.

        * mogstored: kill child processes (diskusage and iostat) when being killed.

2006-11-05:
        * mogstored: set aio threads after daemonizing.  needed by Linux::AIO/IO::AIO, it seems?

2006-09-29
        * mogilefsd: remove non-HTTP mode ("NFS mode") from the server

2006-09-23:
        * mogstored: refuse to start up with missing Linux::AIO/IO::AIO or broken Linux::AIO

2006-09-04:
        * mogstored: set aio_threads as a function of number of disks

2006-07 -> 2006-09
        * mogilefsd: major refactoring/cleanup/new features ("MogileFS 2.0")

2006-03-01 (Brad)
        * mogilefsd: fix dataloss bug when the 'tempfile' table is Innodb and the
           server is restarted while the tempfile table is empty.

2006-02-28 (Jr)
        * mogilefsd: allow create_open to take optional fid parameter which enables you to
        dictate which fid to use internally and to not rely on MySQL's auto_increment

2006-01-10 (Brad)
        * mogilefsd: make Mgd::get_device_summary() always return all devices, regardless
        of status.

        * mogilefsd: update all callers of get_device_summary to filter on the device
        status, if they need to. (provided more clarity into what
        callers' intentions were...)

        * mogilefsd: add a new device state 'readonly' which means: it can be read from
        from clients, it can be replicated from, but no new files can go
        on it or be replicated onto it. and it also reaps, meaning the
        device is fucked. the filesystem probably ate itself.

2005-08-10:
        * mogstored: write out usage files for devices, even if they're not on their own mount point.
          also explicitly include the '-k' flag to df, so we know they're KiB.

2005-08-07:
        * mogstored: new config syntax and command line options
