The /root partition on the vCenter Server is full

Products

• VMware vCenter Server

Issue/Introduction

• A warning message for root disk exhaustion is triggered on the vCenter UI summary page.
• A review of the df -h output shows that the root partition is using more than 80% of its capacity.
• In the VAMI interface (https://<vcenter-FQDN/IP>:5480) >> Summary >> Storage will show a Critical message:

File system /root has run out of storage space.
increase the size of disk /root.

Environment

vCenter 8.x

Cause

• Directory or file which is not required is present under the root directory which is occupying most of the space causing the /root directory to fill up.
• By default only the following directories should be present in the /root directory :

  root@example [ / ]# ls -lrtha
total 84K
lrwxrwxrwx   1 root root    7 MMM DD  YYYY srv -> var/srv
lrwxrwxrwx   1 root root    8 MMM DD  YYYY sbin -> usr/sbin
lrwxrwxrwx   1 root root    9 MMM DD  YYYY media -> run/media
lrwxrwxrwx   1 root root    7 MMM DD  YYYY lib64 -> usr/lib
lrwxrwxrwx   1 root root    7 MMM DD  YYYY lib -> usr/lib
lrwxrwxrwx   1 root root    7 MMM DD  YYYY bin -> usr/bin
drwxr-xr-x  12 root root 4.0K MMM DD  YYYY usr
drwxr-xr-x   5 root root 4.0K MMM DD  YYYY opt
drwxr-xr-x  21 root root 4.0K MMM DD  YYYY ..
drwxr-xr-x  21 root root 4.0K MMM DD  YYYY .
drwx------   2 root root  16K MMM DD  YYYY lost+found
drwxr-xr-x   2 root root 4.0K MMM DD  YYYY rpms
drwxr-xr-x  13 root root 4.0K MMM DD  YYYY home
drwxr-xr-x   2 root root 4.0K MMM DD  YYYY tftpboot
drwxr-xr-x   3 root root 4.0K MMM DD  YYYY .cache
drwxr-xr-x  18 root root 4.0K MMM DD  YYYY var
drwxr-xr-x   3 root root 4.0K MMM DD  YYYY vasecurity
drwxr-xr-x   4 root root 4.0K MMM DD  YYYY mnt
drwxr-xr-x   5 root root 4.0K MMM DD  YYYY boot
drwxr-xr-x 102 root root  12K MMM DD  YYYY etc
drwxr-xr-x  32 root root 4.0K MMM DD  YYYY storage
dr-xr-xr-x  13 root root    0 MMM DD  YYYY sys
dr-xr-xr-x 413 root root    0 MMM DD  YYYY proc
drwxr-xr-x  30 root root 4.4K MMM DD  YYYY dev
drwxr-x---   5 root root 4.0K MMM DD  YYYY root
drwxr-xr-x  40 root root 1.2K MMM DD  YYYY run
drwxrwxrwt  37 root root 1.4K MMM DD  YYYY tmp





• Scenario: vSphere Client (Tomcat) work cache bloat

  • On long-running VCSA systems, the vSphere Client service (vsphere-ui) can accumulate temporary/compiled artifacts in:
    /usr/lib/vmware-vsphere-ui/server/work

  • Expected size: ~100 MB–1 GB. Abnormal: 10 GB+.

  • This content resides on the root filesystem (/), so large growth here directly triggers the VAMI “/root low on storage” alert once / ≥80%.

  How to verify:
  
  # Identify largest areas on /
  du -sh /usr /var /opt /tmp /etc /home 2>/dev/null | sort -h

  # Drill into /usr to confirm vsphere-ui footprint
  du -sh /usr/lib/* 2>/dev/null | sort -h | tail -10
  du -sh /usr/lib/vmware-vsphere-ui/server/* 2>/dev/null | sort -h
  # Journald size (common secondary contributor)
  du -sh /var/log/* 2>/dev/null | sort -h | tail -10
  journalctl --disk-usage
  
  

Resolution

Take a snapshot or backup of the vCenter virtual machine.

If the vCenter is in enhanced linked mode, refer "Snapshot Best practices for vCenter Server Virtual Machines" and "VMware vCenter in Enhanced Linked Mode pre-changes snapshot (online or offline) best practice" for more information.

If vCenter HA is in use on any of the nodes it must be destroyed before attempting this process. refer "Remove a vCenter HA Configuration".

• Access the vCenter virtual machine via SSH using the root account and navigate to the root partition with the following command:

cd /root

• Identify the files that are utilizing the most disk space:

du -shc *

• Use the following command to truncate the file which is not required:

echo > <file-name>

• Use the following command to remove the directory which is not required:

rm -rf <directory-name>

Note : For assistance in deleting directories or truncating files, reach out to Broadcom support.

Resolution – vSphere UI work cache bloat (UI-only restart)

Impact: Brief unavailability of vSphere Client (HTML5) during vsphere-ui restart
No impact: Running VMs, ESXi host connectivity, core vCenter services.

Pre-checks

^{df -h /
service-control --status vsphere-ui
du -sh /usr/lib/vmware-vsphere-ui/server/work}

Steps
# 1) Stop vSphere Client service
service-control --stop vsphere-ui

# 2) Clear Tomcat work cache (safe; auto-regenerated on start)
rm -rf /usr/lib/vmware-vsphere-ui/server/work/*

# 3) Start service and verify
service-control --start vsphere-ui
service-control --status vsphere-ui

Post-checks

• Confirm VAMI → Summary → Storage shows / < 80% and the alert is cleared.
  df -h

• Advise users to refresh their browser tabs after the UI comes back.

• Optional accompanying cleanup – Journald size (non-disruptive)
  
  # Keep last 7 days (adjust to 14/30d or use --vacuum-size)
  journalctl --vacuum-time=7d
  journalctl --disk-usage
  df -h /