Is this server using too much RAM or virtual memory ? (screen attached)

adrianTNT asked:

I have a VPS with 512MB of ram 40GB storage 1CPU, I run a small domain parking service on it.

It is on CentOS, MySQL, Apache, etc.

Now my hosting provider claims that my server is putting too much load on their storage system and they had to reset my instance, and asks me to optimize the server because it is slowing down other clients on the storage.

The total domain’s files (www folder) is under 100MB !

I am looking around and I cannot see what can cause this “storage abuse”, they said it is the virtual memory that is written on their storage, few hundreds MB.

  1. Isn’t this use normal as shown in the webmin screen ?
  2. Does it indicate any problem in the attached “top” command? (e.g the 772MB virtual memory of mysqld).

The only overload that I am aware of is a php script that runs once an hour to process all domain statistics, takes 3 minutes to complete and seems to put the CPU to work 🙂

Edit: I added a second screen of top command showing the missing data above the processes list.

memory usage shown in Webmin

top command output

top command output 2

My answer:

Your httpd processes are using up more RAM than you physically have available, thus something has to get swapped. (It’s also interesting that in the screenshot showing this, you cut off the top, and that you restarted Apache before taking the second screenshot. What are you hiding?) You need to reduce the system’s memory usage dramatically, most likely by reducing the number of simultaneous httpd processes, or get more RAM.

That said, the host should be rate limiting this sort of thing already, which is not too difficult; perhaps they just don’t know how? When you decide to get more RAM (you will), get a new host as well.

View the full question and answer on Server Fault.

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