How to resolve the issue of lack of available space when installing a hard disk on CentOS.

When the hard disk on CentOS has no available space, here are some possible solutions:

1. Clean up unnecessary files: Use the command df -h to check disk usage, then delete unnecessary files or directories to free up space. You can use the command du -sh * to check the size of each directory and remove files that are taking up a lot of space.
2. Compress files: For files that are not needed to be accessed frequently, they can be compressed to save space. Use commands like tar or zip to pack and compress the files, then delete the original files.
3. Delete old log files: Log files may take up a large amount of space. Use the command ls -lh /var/log/ to check the size of the log files and delete the older ones.
4. Remove temporary files: Temporary files in CentOS are typically stored in the /tmp directory. Use the command rm -rf /tmp/* to remove them.
5. Expand partition size: If the size of the disk partition is too small, you can use tools like gparted to increase the size of the partition.
6. Mounting a new hard drive: If the above methods fail to solve the problem, you can consider mounting a new hard drive to expand the available space.

Please make sure to back up important files and data before carrying out any operations to prevent unexpected data loss.