Root disk space
high on-server
What it inspects
`df -P /`, reading the Use% column for the root filesystem. Under 80% passes, 80% to 94% warns, and 95% or more fails. If df gives no usable output, the check is skipped.
Why it matters
A full root filesystem stops logging, databases, package installs and often logins, and services can crash in ways that are hard to recover from. Acting at 80% leaves time to clean up or grow the disk before an outage.
How to verify
df -h /How to fix
Trim old journal entries and the package cache, then find what really uses the space. Larger clean-ups (containers, logs, old kernels) are judgement steps.
Trim the journal and the package cache
Debian / Ubuntu
# Safe clean-up only: old journal entries and the downloaded package cache. This may not free enough;
# the next step shows how to find what is really using the space.
# Journal entries older than 14 days are deleted: keep a copy first if you need them for an investigation.
journalctl --vacuum-time=14d
apt-get clean
df -h /
RHEL / Rocky / Alma / Fedora
# Safe clean-up only: old journal entries and the downloaded package cache. This may not free enough;
# the next step shows how to find what is really using the space.
# Journal entries older than 14 days are deleted: keep a copy first if you need them for an investigation.
journalctl --vacuum-time=14d
dnf clean all
df -h /
- Find what is using the space and decide what goes
1 more step in the Fix Pack. See pricing