（5）ceph RBD快照

[[email?protected] alertscripts]# rbd showmapped
id pool namespace image       snap device    
0  rbd            remote_rbd1 -    /dev/rbd0

（1）rbd已经mount在mnt目录

[[email?protected] alertscripts]# df -h 
Filesystem               Size  Used Avail Use% Mounted on
/dev/rbd0                150G  9.8G  141G   7% /mnt

（2）在/mnt下创建2个测试文件

[[email?protected] mnt]# ls
ceph-file  test  test1

（3）服务器端做快照
语法：
rbd snap create<pool-name>/<image-name> @<snap-name

[[email?protected] ~]# rbd snap create rbd/[email?protected]
[[email?protected] ~]# rbd snap ls rbd/remote_rbd1
SNAPID NAME  SIZE    PROTECTED TIMESTAMP                
snap1 150 GiB           Wed Aug 28 15:33:35 2019

（4）测试快照恢复功能，在客户端删除2个test 文件

[[email?protected] mnt]# ls
ceph-file  test  test1
[[email?protected] mnt]# rm -fr *

（5）客户端umount 挂载，取消map rbd 映射

[[email?protected] /]# umount  /mnt/
[[email?protected] /]# rbd unmap remote_rbd1

注释：如果不执行上面的卸载命令和取消映射就会出现如下报错

[[email?protected] /]# rbd snap rollback  rbd/[email?protected]
Rolling back to snapshot: 0% complete...failed.
rbd: rollback failed: (30) Read-only file system

（6）通过快照进行回滚，注意快照回滚，之前的数据会被覆盖
语法：rbd snap rollback pool-name>/< image-name> @<snap-name

[[email?protected] /]# rbd snap rollback  rbd/[email?protected]
Rolling back to snapshot: 100% complete...done.

（7）重新挂在检查，原来的文件恢复

[[email?protected] /]# rbd map remote_rbd1
/dev/rbd0
[[email?protected] /]# mount /dev/rbd0 /mnt/
[[email?protected] /]# df -h 
Filesystem               Size  Used Avail Use% Mounted on
/dev/mapper/centos-root   46G   12G   34G  27% /
devtmpfs                 7.8G     0  7.8G   0% /dev
tmpfs                    7.8G     0  7.8G   0% /dev/shm
tmpfs                    7.8G  113M  7.7G   2% /run
tmpfs                    7.8G     0  7.8G   0% /sys/fs/cgroup
/dev/sda1               1014M  180M  835M  18% /boot
tmpfs                    1.6G     0  1.6G   0% /run/user/0
/dev/rbd0                150G   33M  150G   1% /mnt
[[email?protected] /]# cd /mnt/
[[email?protected] mnt]# ls
test  test1

（8）当不再需要某个快照时，可以使用如下命令删除指定的快照 删除快照不会删除 Ceph RBD 镜像巾当前的数据:

[[email?protected] /]# rbd snap rm rbd/[email?protected]
Removing snap: 100% complete...done.