Three elements to be followed in data Center shutdown maintenance

In the process of daily operation and maintenance, shutdown operations such as power outage, equipment inspection and maintenance, system migration and so on are often encountered. After shutdown, it is inevitable to encounter the phenomenon that the system cannot be started and the data is lost, which requires that the OPS project needs to make sufficient preparations before downtime and maintenance. The following are the operation steps of shutdown maintenance in my work summary: 1. Data backup: do a good data backup by using scripts, FTP, tar, tape and other methods before shutdown. Be sure to stop service before backup, so as to avoid data differences. 2. The downtime order of application servers is DB- > WEB- > Peripheral system-> LB- > storage- > network divices, which is suitable for downtime maintenance of data center as a whole. 3, the system shutdown sequence: (1) stop the application service (2) check whether the system has other users online, use the who command to check. (3) check the online status of the network and use the netstat-a command to view it. (4) verify that the applications are stopped, and check it with the ps-aux command. (5) data synchronization, during shutdown and restart maintenance operations, you must use the sync command to synchronize data from memory to the hard disk. (6) shutdown- > reboot- > halt do a good job in the above three points, which greatly avoids the failure rate of the system after shutdown and maintenance. The specification of operation and maintenance personnel must be followed, and we must form a habit. Please add any of the above omissions.