sftp启动方法

Step 1. back up older config file:
cp /etc/ssh/sshd_config /etc/ssh/sshd_config.bak

Step 2. vi /etc/ssh/sshd_config
Step 3. set below items or replace it with below content:
UsePAM yes
PermitUserEnvironment yes
Subsystem sftp /usr/libexec/openssh/sftp-server

Step 4.  /sbin/service sshd restart