Score:0

Multiple core overload on Ubuntu

cn flag
a b

I have a really strange behavior of the server. I run Apache, MySQL, WordPress on it. And recently, it has had a lot of freezes. MySQL/Apache shows high CPU usage (out of 24 cores - 2400% cpu% according to the htop). At first, I thought that the cause of this was MySQL or Apache. So I've tuned the DB, I've turned off the Apache, I've disabled external access to the server, in case it was a DDOS attack. But the problem remains.

Even when I turn off Apache and MySQL, the problem is still there. Not so critical, but the simple commands use a lot of CPU and take a lot of time to run.

Now my thoughts are that something on the lower level is broken.

Here are the perf top and htop outputs:

perf top htop

Could it be, that the reason is the internal gnu-linux functions? And if so, how can one fix it?

Nikita Kipriyanov avatar
za flag
I see two tar-gzip running, eating 4 CPUs in total. Why those are there right now? Also, fail2ban makes things *worse* under DDoS attack. What it is doing ringt now, why it eats a core?
djdomi avatar
za flag
i agree with nikita, only seeing a tar which runs, no apache - wrong screenshot? - loadlevel 22/24 is not much - it could go 48 in case of hyperthreading with no issue...
a b avatar
cn flag
a b
I am using the tar for the backup of the website files. The apache is turned off, as well as mysql. My point here is that something is using a lot of cpu, and at first I thought about apache or mysql, but as you can see, they're not the causes. So, maybe I can provide some additional information, that will help. Because right now, I have no idea what is going on. Thank you
Wilson Hauck avatar
jp flag
With your 32B server, ENABLE a 6GB SWAP SPACE to encourage survival when busy. Even though you have 24 cores, limiting to 10 running will minimize the constant struggle of what is going to run when resources are available. Additional information request. Any SSD or NVME devices on MySQL Host server? Post on pastebin.com and share the links. From your SSH login root, Text results of: B) SHOW GLOBAL STATUS; after minimum 24 hours UPTIME C) SHOW GLOBAL VARIABLES; D) SHOW FULL PROCESSLIST; for server workload tuning analysis to provide suggestions.
Wilson Hauck avatar
jp flag
What is the purpose of THREE copies of top running? Sounds like someone does not know how to terminate Command Prompt activity, so it just runs on and on. See https://mysqlservertuning.com/pages/faq for tips on stopping your activities.
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