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2./dev/shm

The size of the Linux default (CentOS)/DEV/SHM partition is 50% of the system's physical memory, although the use of/DEV/SHM is much more efficient for file operations.
However, it is seldom used in the current release software (except for Oracle mentioned earlier) and can be viewed through LS/DEV/SHM to see if there are any files below, and if not, the current system does not use the device.

1.Error, some other host already uses address

Event:
Today to help customers reinstall the system, just start the network is normal, IP is installed in the process of configuration. However, after modifying the Ifcfg-eth0 file to restart the network service, there will be "error, some other host already uses address" error, and the network does not pass. Tried multiple methods, including reinstalling the system, and eventually the problem was the same.
Here's how to fix it:
Vi/etc/sysconfig/network-scripts/ifup-eth
Comment out the following lines and then execute the service network restart
#if! /sbin/arping-q-C 2-w-i ${realdevice} ${ipaddr}; Then
# echo {1}quot; Error, some other host already uses address ${ipaddr}. "
# exit 1
#fi

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