今天研发反馈说我们有几台服务器通过NFS挂载到存储服务器的，数据突然不同步，于是我在晚上线上生产停止后对几台服务器重新挂载观察情况，中途出现了umount 报device is busy的情况。

Linux umount报device is busy

[xiaoshuai.zhu@198-51-100-11 ~]# df -h  
文件系统                                   容量  已用  可用 已用% 挂载点  
/dev/sdb3                                  2.1T  378G  1.7T   19% /  
devtmpfs                                    32G     0   32G    0% /dev  
tmpfs                                       32G     0   32G    0% /dev/shm  
tmpfs                                       32G  681M   31G    3% /run  
tmpfs                                       32G     0   32G    0% /sys/fs/cgroup  
/dev/sdb2                                  190M  140M   37M   80% /boot  
tmpfs                                      6.3G     0  6.3G    0% /run/user/0  
/dev/sda1                                  447G  354G   94G   80% /data/mysql_ssd  
198.51.100.10:/data/data11  5.0T  123G  4.9T    3% /data/share
[xiaoshuai.zhu@198-51-100-11 ~]#
[xiaoshuai.zhu@198-51-100-11 ~]# umount -t nfs 198.51.100.10:/data/data11 /data/share  
umount.nfs4: /data/share: device is busy
umount.nfs4: /data/share: device is busy

解决方式

[xiaoshuai.zhu@198-51-100-11 ~]# yum install -y psmisc  
[xiaoshuai.zhu@198-51-100-11 ~]# fuser -km /data/share/  
/data/share:         30707 30708  
[xiaoshuai.zhu@198-51-100-11 ~]# umount -t nfs 198.51.100.10:/data/data11 /data/share  
umount: /data/share：未挂载