磁盘空间清理及分区安全性咨询

Hey there! Let's walk through your disk space questions clearly and safely.

First, let's figure out what /dev/md1p1 actually holds—since it starts with md, this is a software RAID partition, and it's almost certainly your root filesystem (/) where your operating system, installed apps, user data, and system configs live. You absolutely can't empty it entirely, but there are plenty of safe ways to free up space on it.

To confirm exactly where it's mounted, run this command in your terminal:

df -h /dev/md1p1

If the output shows / as the mount point, that's your root partition—here's what you can safely clean up:

Safe cleanup targets on /dev/md1p1 (root partition) #

• Temporary files: Directories like /tmp and /var/tmp store short-term data that's usually safe to delete. You can run:

  sudo rm -rf /tmp/*
  sudo rm -rf /var/tmp/*
  

  Note: Any files currently in use by running apps might throw errors, but these directories are automatically cleared on system reboot anyway. For automated cleanup, use sudo tmpwatch (RHEL/CentOS) or sudo tmpreaper (Debian/Ubuntu).

• System logs: The /var/log directory can bloat over time. To clean systemd logs safely, run:

  sudo journalctl --vacuum-size=1G
  

  This keeps only the last 1GB of logs. You can also delete old compressed log files (ending with .log.gz) manually—just avoid deleting active, uncompressed log files.

• Package manager cache: If you use Debian/Ubuntu, clear old package archives with:

  sudo apt clean  # Removes all downloaded package files
  sudo apt autoclean  # Only removes outdated package files
  

  For RHEL/CentOS/Fedora, use:

  sudo dnf clean all
  

• User-specific caches: Your home directory's ~/.cache folder stores app cache data (like browser history, thumbnails, etc.). You can delete this safely with:

  rm -rf ~/.cache/*
  

  This won't delete your personal files, just temporary app data.

Other partitions: What to clean (and what to leave alone) #

Since you didn't list other partitions, here's a general guide:

• /home partition: This is where your personal documents, photos, downloads, etc., live. Don't empty it entirely, but you can safely delete old downloads, unused apps, or large files you no longer need. Use du -sh ~/* to find big folders in your home directory.
• /var partition: If this is a separate partition, focus on /var/log (logs) and /var/cache (package caches) as mentioned above. Never delete /var/lib—it contains critical data like databases and system state files.
• Swap partitions: These are used for virtual memory—never delete or format them while the system is running.

Critical safety tips before cleaning #

1. Backup first: Always back up any important files you're unsure about before deleting anything.
2. Check what's taking space: Use du -sh /path/to/directory to identify large folders. For example, du -sh /* will show you which top-level directories are using the most space on your root partition.
3. Don't delete system core files: Avoid touching directories like /bin, /sbin, /usr/bin, or /etc unless you're 100% certain the files inside are unnecessary. Deleting these can break your system.
4. Check active files: If you're unsure if a file is in use, run lsof /path/to/file—this will show you which processes are accessing it.

备注：内容来源于stack exchange，提问作者nando promo