[root@ceph1 ceph_centos8_x86_64]# ceph fs new cephfs cephfs_metadata cephfs_data
new fs with metadata pool 3 and data pool 2
[root@ceph1 ceph_centos8_x86_64]# ceph health detail
HEALTH_ERR 1 filesystem is offline; 1 filesystem is online with fewer MDS than max_mds
[ERR] MDS_ALL_DOWN: 1 filesystem is offline
fs cephfs is offline because no MDS is active for it.
[WRN] MDS_UP_LESS_THAN_MAX: 1 filesystem is online with fewer MDS than max_mds
fs cephfs has 0 MDS online, but wants 1
在创建cephfs的时候，ceph集群出现这种问题怎么处理？
你的节点状态是否正常？
报错提示你，没可用的MDS，都offline 了。。。
先确保集群节点正常，没其余异常，然后MDS相关也设置好。