Hello everyone！
I will share a question about packet loss on U2000 server.
Problem Description：
Packet loss occurs between the active and standby U2000 servers. The packet loss rate is 30%.
Troubleshooting：
1. Check the network layer and ensure that no problem occurs.
2. Check the configuration of the disk array. Sometimes, if the configuration of the disk array on the two servers does not match, packet loss occurs. No exception is found in the check result.
3. Check the parameters of the U2000 server. No problem is found.
4. When the ping test is performed, it is found that a large packet larger than 1300 bits cannot reach the peer end. After consultation, the two active and standby servers are supported by a third-party network device. Because the device is old, the MTU value is 1300 bits and cannot be changed, therefore, only the MTU value of the network port of the U2000 server needs to be changed to adapt to the third-party network device.
5. After the MTU of the network port on the U2000 server is reduced from 1400 to 1300, the fault is rectified.
Root Cause：
Two U2000 active and standby servers are supported by a third-party network device. The device is old and the MTU value is too small and cannot be changed.
Solution Description：
Change the MTU Value of the Network Port of the U2000 Server
The following describes how to change the MTU of the server：
Method 1: temporary change method
ifconfig bond1 MTU 1400，
After changing, query MTU：
netstat –i
Method 2: permanent change method
Edit below file：
/etc/sysconfig/network
Find the file ifcfg-*，modify MTU
After modifying, save this file and restart the network service :
service network restart
