# What is DMirror
- DMirror is a real-time directory sync tool, used for local and remote file sync. Compare to DRBD, DMirror has these features:
  - 1, DMirror is built on application level, on the top of file system
  - 2, DMirror's slave can be read, even write
  - 3, DMirror can switch master with slave very easy
  - 4, DMirror has a monitor HTTP display page

# How to use
  - 0.1, set /proc/sys/fs/inotify/max_user_watches and /proc/sys/fs/inotify/max_queued_events to proper number
  - 0.2, set local and remote rsync dir
  - 1, start master, ./dmirror mainbase dmirror1.ini
  - 2, start slave, ./dmirror mainbase dmirror2.ini
  - 3, curl "http://your_master_ip:your_master_port/setmaster" to start master-slave sync
  - 4, when you want to switch master-slave, curl "http://your_slave_ip:your_slave_port/setmaster" to start a new slave-master sync

# How DMirror works
  - depend on rsync(recommend 3.0.9),inotify(kernal 2.6.13+), and file system
  - DMirror has 3 process roles:
    1, mainbase: accepet HTTP command, communicate with other processes by UNIX socket, monitor other processes, and control all state-transition
    2, watcher: use inotify to watch what file created,deleted,modified and write to RLog
    3, sender: read from RLog and send rsync command to remote

# Supported HTTP command
  - setmaster
  - setslave
  - getstate
  - getstatus(HTML)
  - showconf
  - updateconf

# Author
  kobe, feedback [email protected]
  thanks renzhong to test