Suddenly websites loading extremely slow - yet WHM & server appears fine

[david26uk]

Hi Guys,

Last night I noticed websites on my dedicated server loading extremely slow. Here's a breakdown of the details and what I've checked thus far:

- every 3-5 minutes it returns to normal, websites load fast again.
- CPU, memory & disk usage appear fine
- Logs show no unauthorised IP's accessing the server, no unusual messages
- Checked for attacks, no duplicate IP's or excessive requests. Bandwidth is normal.
- files, scripts etc on the server haven't changed, been loading fast for months without issues
- checked on various browsers, other computers
- Strangely, some pages load fine
- about 60 domains on server in total (50+ add-on domains)

It feels like a cocktail of mixed signals and I'm struggling here. Any help would be greatly appreciated.

Thank you

 

[cPanelMichael]

Hello

The following thread is a good place to start, and includes useful advice on troubleshooting load and slowness:

Troubleshooting High Loads On Linux Servers

Thank you.

 

[david26uk]

Thank you for the guide - unfortunately it hasn't solved the problem.

- CPU & memory usage are low, load average is 0.5.
- tcpdump log not showing duplicate IP's (only search spiders)

Any further ideas to check? Do you think this could be a sign of hard disk failure?

Thanks

 

[cPanelMichael]

You could check /var/log/messages and /var/log/dmesg to see if you notice anything out of the ordinary that would indicate a failing hard drive. Your data center may also be able to assist you with this issue.

Thank you.

 

[kdean]

Note that it's possible for data center networking issues to cause this effect even when an attack is not directed at your server. Check Pings and Traceroutes to the server during when it's having issues to see if there is any packet loss.