$ ceph mds stat
test_fs-1/1/1 up test1_fs-1/1/1 up  {[test1_fs:0]=ceph-xx-osd03.gz01=up:active,[test_fs:0]=ceph-xx-osd00=up:active}

$ ceph mds dump
dumped fsmap epoch 50
fs_name	test_fs
epoch	50
flags	4
created	2017-09-05 10:06:56.343105
modified	2017-09-05 10:06:56.343105
tableserver	0
root	0
session_timeout	60
session_autoclose	300
max_file_size	1099511627776
last_failure	0
last_failure_osd_epoch	4787
compat	compat={},rocompat={},incompat={1=base v0.20,2=client writeable ranges,3=default file layouts on dirs,4=dir inode in separate object,5=mds uses versioned encoding,6=dirfrag is stored in omap,8=file layout v2}
max_mds	1
in	0
up	{0=104262}
failed
damaged
stopped
data_pools	[2]
metadata_pool	3
inline_data	disabled
balancer
standby_count_wanted	1
104262:	100.0.0.34:6800/1897776151 'ceph-xx-osd00' mds.0.37 up:active seq 151200

$ ceph mds rm 0 mds.ceph-xx-osd00

$ ceph mds add_data_pool <pool>

$ ceph mds cluster_down
marked fsmap DOWN

$ ceph mds cluster_up
unmarked fsmap DOWN

$ ceph mds compat rm_compat <int[0-]>

$ ceph mds compat rm_incompat <int[0-]>

$ ceph mds compat show

$ ceph mds remove_data_pool <pool>

$ ceph mds stop <node1>

$ ceph mds tell <node> <args> [<args>...]

#添加一个机器 new_host 到现有mds集群中 
su - ceph  -c "ceph-deploy --ceph-conf /etc/ceph/ceph.conf  mds create $new_host"

ceph daemon mds.ceph-xx-mds01.gz01 session ls