Solve the vswitch reboot failure for no reason

The author uses floor switches to connect to an E-government intranet that is physically isolated from the Internet for online office work. Other units in the entire administrative building also use the same method, connect to the E-Government Intranet platform for administrative approval, administrative penalties, and electronic supervision. In order to ensure the efficient and stable operation of the E-government intranet platform, the building network administrator should inspect the network equipment distributed on each floor almost every day to detect various possible problems in time.

Vswitch reboot without reason

Recently, during normal inspection, the building network administrator found that all port lights of a vswitch on the fourth floor were not on, and the power indicator lights of the vswitch were not on, all client systems connected to the vswitch on this floor cannot access the Internet normally. After careful inspection, the network administrator finds that the power supply module of the vswitch may have problems, resulting in the failure of the power supply. For such a hardware fault, only a new switch can be replaced in a short period of time to solve the problem that the client system cannot access the Internet normally. The Network Administrator immediately finds a backup switch of the same type from the warehouse, arriving at the fault site, connecting the physical cable and powering on the power for START, the original thought that after such a simple replacement operation, the network failure can be resolved immediately; however, in the process of replacing the switch, the Network Administrator finds that each time the switch is started stably, it will be inexplicably restarted. What is the problem? Is there a problem with this backup switch of the same model? The standby switch has been in the warehouse of the network management center of the building for more than a year. It has been tested before and its working status is normal, so I will keep it at hand for future unexpected needs. Now it's hard to make use of it. How can we get this backup device out of the chain at the crucial moment? Therefore, the network administrator decided to perform a comprehensive inspection and test on the slave switch to see if it was a real illness or an outfit.

Tracking Fault Causes

After the standby switch is connected to the E-Government Intranet platform of the building, it is often restarted for no reason. To facilitate fault tracking, the network administrator specially disconnects it from the E-government intranet network, use the console control port to connect to the laptop separately. After the physical cables are connected, the network administrator clicks the start, program, attachment, communication, and Super Terminal menu options in the notebook, open the Super Terminal Program interface, and create a super terminal connection that communicates directly with the backup switch. When the backup switch is stable, enter the Super Terminal control window; when the standby switch restarts again, the network administrator in the Super Terminal control window saw the switch background system prompt that a bus fault was encountered during the startup, this bus-type fault may cause the standby switch to not work stably for a long time.

At first, the network administrator suspected that there was a problem with the system image file of the backup switch, which caused the switch's background system to fail to run properly. Now, through monitoring the Startup Process of the switch in the Super Terminal control window, the network administrator finds that the system image file of the switch has been successfully loaded and started to run, this indicates that the reboot failure of the switch has nothing to do with the system image file, and you do not need to download the latest version of the system image file from the Internet.

Since the standby switch has a bus fault during startup, most of the problem lies in the switch's bus. Considering that the bus is generally located on the switch's motherboard, the Network Administrator subconsciously believes that the main board of the switch may have problems. Over the years, the maintenance habits prompted the network administrator to decide to open the shell of the backup switch and check whether the corresponding motherboard has obvious problems. To achieve this, the network administrator immediately finds a screwdriver, unscrew all the screws on the back of the switch, remove the switch housing, remove the motherboard of the switch, and observe every electronic component on the motherboard With a magnifier, no obvious signs of burning were found, but the surface of each electronic component was covered with a large amount of dust. Is it that these dust was secretly "messy "? In order to eliminate the dust, the network administrator decided to clean the dust on the surface of the Main Board Components first. To do so, the network administrator immediately started to use a soft and small brush dedicated to cleaning the computer motherboard dust, we carefully cleaned all the "corners" of the Main Board.

After confirming that the dust is cleaned, the Network Administrator carefully restores the motherboard of the switch to the original position according to the correct operation method, installs the switch housing, and tighten the fixing screws. Then, connect the physical cable, connect the input power of the switch, and observe through the Super Terminal monitoring window. The network administrator can see that the switch startup sequence is normal and can enter the switch background configuration interface, this surprised the network administrator. During this startup, the network administrator did not find the system prompts that there was a bus type error. Is it true that the switch is working normally after the dust on the surface of the switch element is cleared? The Network Administrator is still a little worried. He once again cut off the power of the backup switch. After a while, he re-connected the power source and asked the switch system to restart, during the startup process, he monitored through the Super Terminal Program window that the switch caused a normal sequence, and no prompt of bus errors was found, it seems that the problem is caused by the dust on the surface of the electronic components of the switch.

Fault summary and reflection

After careful analysis, the network administrator believes that the standby switch that has been stored in the warehouse of the building data room is constantly restarted due to the inconspicuous dust. After inspection, we found that the sanitary environment of the data center warehouse in the building was very poor. After the building was built, the warehouse had almost never been cleaned, and the floors, walls, and other corners inside it, there is dust everywhere, and people can leave clear footprints when walking around the warehouse floor. In this dusty environment, the backup switch is packed, the dust will slide to the inside of the switch chassis, covering the surface of electronic components. In addition, the normal ventilation of the building data room warehouse is not good, and the standby switch is placed in it for a long time, which leads to more and more dust on the surface of electronic components, in addition, dust absorbs water vapor in the air, causing the surface of the electronic components to become very wet. Therefore, after the network administrator connects to the power of the switch, it is easy to encounter a fault similar to a bus error. In severe cases, can directly burn the electronic components of the switch. In this case, although the dust in the air is not very good, it has a great impact on network devices such as switches.

In order to ensure that the LAN can always run stably, we recommend that network administrators clean network equipment on a regular basis in addition to network management and maintenance, at the same time, ensure that the network equipment can always work in a clean and clean environment. In addition, you also need to conduct regular power-on tests on the standby network equipment that has been stored in order to prevent the above faults from happening again.