How to Run Traceroute and Ping, Troubleshoot High Disk I/O, and Use cPanel & WHM Inside Linux Containers

1. Running the traceroute Command

The traceroute utility shows the path that network packets take from your machine to a destination host.

macOS or Linux

If the server restricts traceroute, connect via SSH as a privileged user such as root.

traceroute example.com

Example output:

traceroute to example.com (192.168.0.20)
 1  gateway (192.168.0.20)
 2  10.1.0.1
 3  vl118.ss-core.example.com

Microsoft Windows

Windows uses the tracert command.

tracert example.com

Example output:

Tracing route to example.com [192.168.0.20]
 1  2ms  1ms  1ms 192.168.0.20
 2  7ms  7ms  9ms 192.168.0.20
 3  11ms 11ms 11ms 192.168.0.20

2. Running the ping Command

The ping command tests latency between your machine and a target host.

macOS or Linux

ping example.com

Example output:

PING example.com (192.168.0.20)
64 bytes from 192.168.0.20: time=22.122 ms

Microsoft Windows

ping example.com

Example output:

Reply from 192.168.0.20: bytes=64 time=22ms ttl=45

3. Troubleshooting High Disk I/O

Disk I/O refers to how long read/write operations take on a hard disk. High I/O wait slows down the entire server.

Symptoms of High Disk I/O

• High server load
• chkservd offline service notifications
• Slow websites
• Slow Exim or large mail queue
• Slow POP/IMAP connections
• Slow Webmail
• Slow WHM or cPanel interfaces

Check Disk I/O Wait with top

The %wa value shows disk wait time.

Check Historical I/O with sar

sar -d

How to Fix High Disk I/O

• Upgrade to faster disks (SSD recommended)
• Enable write caching
• Check RAID for hardware issues
• Distribute load across multiple disks

Enable DMA

hdparm -d1 /dev/hda

Disable DMA

hdparm -d0 /dev/hda

Test Disk Speed

hdparm -Tt /dev/hda

4. Running cPanel & WHM Inside Linux Containers (LXC)

Warning: Only experienced system administrators should perform these steps.

Recommended Host OS

Best compatibility: RHEL 7 or CentOS 7

Guest OS Requirements

CentOS 7 or RHEL 7 require additional configuration.

Privileged vs Unprivileged Containers

cPanel works in both, but privileged containers are strongly recommended.

Unprivileged Container Limitations

• root is treated as a non-root user
• Cannot raise hard limits after lowering them
• Possible subtle behavior differences

Required Changes for CentOS 7 / RHEL 7

Update lxc.conf:

lxc.include = /usr/share/lxc/config/fedora.common.conf

Disable capabilities:

# lxc.cap.drop = setpcap
# lxc.cap.drop = setfcap

Fix cron Issues in LXC

Edit /etc/pam.d/crond and comment out:

#session    required    pam_loginuid.so

AppArmor Configuration

For newer versions:

lxc.apparmor.profile = unconfined

Conclusion

This guide covers how to run traceroute and ping, how to diagnose and fix high disk I/O, and how to configure cPanel & WHM inside LXC containers. Following these steps ensures better performance, stability, and compatibility for your server.