How to clear disk space on CentOS/RHEL 6, 7, 8?

Updated: 28 September 2026 · Applies to: Ubuntu 24.04, Debian 12, AlmaLinux 9 and Rocky Linux 9

CentOS 6/7/8 are end of life; these steps are for Ubuntu 24.04, Debian 12, AlmaLinux 9 and Rocky Linux 9. Do not run cleanup scripts from the internet that you have not read: find out what uses the space first, then remove only what you understand.

1. Find what uses the space

df -h                                            # which file system is full
du -xh / --max-depth=1 2>/dev/null | sort -h     # biggest top-level folders
find / -xdev -type f -size +500M -exec ls -lh {} \;   # files over 500 MB

ncdu -x / (from EPEL, or apt install ncdu) lets you browse sizes interactively.

2. Safe cleanups

dnf clean all                         # AlmaLinux / Rocky package cache
dnf remove --oldinstallonly           # old kernels (keeps the running one)
apt clean && apt autoremove --purge   # Ubuntu / Debian
journalctl --disk-usage
journalctl --vacuum-size=200M         # shrink the systemd journal

To keep the journal small permanently, set SystemMaxUse=200M in /etc/systemd/journald.conf and restart systemd-journald.

3. Large log files

Empty a log that a program still writes to with truncate -s 0 /var/log/big.log (deleting it does not free the space until the program restarts). Then check that logrotate handles it: see /etc/logrotate.d/.

4. Space not freed after deleting

A running program may still hold the deleted file open. Find it with lsof +L1 and restart that service.

Other common space users

• Old backups and archives in /root, /home or /backup.
• Docker images and volumes: check with docker system df.
• On cPanel accounts, use Files › Disk Usage in cPanel to see which folders are large, and empty old email with the Email Disk Usage tool.

Note: Never delete files in /var/lib/mysql by hand. Drop databases you no longer need from MariaDB/MySQL, or ask our support team.