现象：sshfs总是断连，访问mount点，出现 ls: cannot access 'sshfs': Input/output error
原因初探：是底层的ssh连接session断开
解决：想办法保持底层ssh连接session长连接。有很多方式，最简单、最直接的，就是为sshfs提供ssh连接选项 “ServerAliveInterval”
as of：
#sshfs -o sshfs_sync,reconnect,ServerAliveInterval=60 sshfs@10.1.101.3:/data/data1 /sshfs
#sshfs -o sshfs_sync,reconnect,ServerAliveInterval=60 sshfs@10.1.101.3:/data/data1 /sshfs
#sshfs -o sshfs_sync,reconnect,ServerAliveInterval=60 sshfs@10.1.101.3:/data/data1 /sshfs
#sshfs -o sshfs_sync,reconnect,ServerAliveInterval=60 sshfs@10.1.101.3:/data/data1 /sshfs
#sshfs -o sshfs_sync,reconnect,ServerAliveInterval=60 sshfs@10.1.101.3:/data/data1 /sshfs
#sshfs -o sshfs_sync,reconnect,ServerAliveInterval=60 sshfs@10.1.101.3:/data/data1 /sshfs