Event: On the way to build a cloud computing management platform of CAS Centos7.4 virtual machine after a power failure, the virtual machine appears file '/grub/i386-pc/normal.mod' not found, use the Internet are the brightest Great God on the back is not resolved, the entire storage volume will mount the same system virtual machine and mount the / boot partition where the last copy files in the machine / boot directory to the mounted, unmount the disk, re-hang back to the original virtual machine start the virtual machine successfully
Figure:
Orientation:
Boot error as follows
View directory by ls, and one by one tried later, I found my / boot partition is in the (hd0, msdos1), you can try using ls (hd0, msdos1) / see whether the directory, you can also (hd0 ls, msdos1 ) to see if the system will display the file
Figure:
The following msdos1 is we're looking for a partition, but in this partition is only a document indicating the other files in / boot are lost
Solve the problem:
After find the root cause of the problem, try to resolve it, first of all we remove the storage volume to a virtual machine, and then add the virtual machine to another of the same system, and mount to see, because we know when they are dividing partition which partitions , so the problem becomes relatively easier, I was the / boot directory is divided into / vda1 partition, but after vdb mount is mounted, so the / boot should be / dev / vdb1, mount the device to after you create a good directory, copy the native files in the / boot, unloading equipment, re-add storage volume to the original virtual machine starts, started successfully.
Figure:
1, first delete the storage volume and then added to the same system, the same as other system partition (CAS platform is not a principle similar)
2, into the linux system, confirm the partition, began to mount and copy files
Because the environment is cloned, so that when mounting vdb1, there already exists an error display uuid, we check to filter out the UUID parameter or regenerate UUID, to a second election
or 
After a successful mount, copy files
3, unloading equipment, storage volume is added to the original virtual machine and start, start success
