Site very slow, High TTFB, what happened?

[yu0307]

So I started to have this issue, Every page I load I notice there is a high TTFB (2-10s). Regardless if it's a brand new wordpress site or not. It seems that delay before first byte is always there.

I suspect it's a Mysql or caching issue, but I turned on cache on both mysql and apache(opCache). there is no improvements.

I'm running on Cent 7 with Cpanel 64. System is virtualized on VMware with 12 CPus and 64Gb memory. the Internet is fine, because i have another VM running on the same network and that webserver has no TTFB issue.

I notice even uploading through SSH is a bit slow.

Please help, or let me know how I can debug and find out the issue.

Thank you

 

[cPanelMichael]

Hello,

You may find the discussion of this topic on the following thread helpful (and the threads linked within it):

SOLVED - How to debug slow response time when load average is already low?

Thank you.

 

[yu0307]

Hi, Thank you for your response, The reference did point out the issue.
- Cached sites are super fast.
-It's only slow when logged into wordpress and then visit the site.
suspecting it's a apache and Mysql Issue.
I read all the referencing site, the only suggestion is using litespeed which I don't want to do since it cost $2k to buy one with 8 cores. I'm going to try to upgrade to EA4 and PHP7 and see the result.
Any further suggestions?

 

[cPanelMichael]

Any further suggestions?

Are you using any Mod_Security rules? If so, you may want to disable them to determine if they are the culprit, as was the case in this post:

Extremely slow TTFB

Thank you.