"An unknown error has occured" during installation

nexus

Problem description: “An unknown error has occurred” when installing

Problem analysis:
Reason 1:There is other residual dirty data on the hard disk, you need to use dd to format the disk;
Reason 2: USB drive burning problem, ISO is incomplete or incomplete after burning, improper USB drive plugging and unplugging may also cause USB drive data damage

Problem handling process:

The hard disk to be installed has dirty data, use dd to format it and execute

dd if=/dev/zero of=/dev/sdX bs=10M count=100

Where: sdX is the disk symbol of the system to be installed, use fdisk to view
To format the disk, write 100 consecutive blocks of 10MB binary zeros to the target disk, resulting in approximately 1GB of zero data being written in total.

Clear the metadata on the hard disk, Ctrl + alt +F5 to enter the command line

dmraid -r -E /dev/sd<x>

Verify whether the ISO md5 is correct
Whether the USB drive burning is complete, whether the USB itself has problems
Whether there is a problem with the server USB interface
IPMI network fluctuations cause CD-ROM not to be mounted