merge with master and modify iGet but not right yet.
merge with zhaoyang and modify to solve conflicts
alter iget() about cx.
merge with master
modify iGet() for cx client.
merge with master
add data balance.(but the delSFL interface has not achieved)
modify databalance delSFileLocation.
merge with origin/zhaoyang
merge with master
Merge remote-tracking branch 'origin/zhaoyang' into zhuqihan
alter metastoreclient add data balance.
Merge remote-tracking branch 'origin/macan' into zhaoyang
change MonitorHandler avoid removing everything in datacount/
Merge remote-tracking branch 'origin/macan' into zhaoyang
add MsgStorage.java into dservice.
merge with master and fix conflict
add MsgConsumer for metadata backup
Merge remote-tracking branch 'origin/zhuqihan' into zhaoyang
a framework of databak