I need an idea to solve overloading my server, my server specification:

vCPUs: 1 vCPU

Memory: 2 GB

System Drive: 40GB

OS:Linux Ubuntu 10.04 64 bit

Software: Apache, PHP, MySQL, and Plesk 11

I check the server using command htop, showing me 1900MB of 2000MB usage and swap 1600MB of 3000MB. When that happens, all my domains (about 30) are not loading and I can't do anything. To solve this I always have to restart the machine.

Processes looks OK, nothing wrong, few MySQL and psa (Plesk).

On server I've got 10 WordPress and about 3 other CMS websites.

Do I really need more RAM or maybe another VPS?

Please help me to choose...

  • 1
    More RAM...2 GB is not nearly enough. Also, see: serverfault.com/questions/29126/… – Nathan C Jun 18 '13 at 12:11
  • also: Swap usage on VM's is EVIL - you share disc IO, so you get very slow fast. That you use 1600mb of 3000 already shows something is SERIOUSOSLY off. – TomTom Jun 18 '13 at 12:57

If you're more than about 100MB into swap, you need more memory. At least, that's the general rule I use when evaluating performance issues.

  • I have and option "Temporary Upgrades" from my provider, I should upgrade memory for a couple of weeks and test it... It cost only 5 pound to upgrade to to 4 GB. – Jerry Jun 18 '13 at 12:28
  • Given that, then yes I would upgrade temporarily. The situation will improve, but you may still end up going into swap depending on how heavily used your server is. You'll almost never see CPU issues with web servers, but memory issues are fairly frequent. You may need to upgrade to 8GB memory, again depending on observed usage levels. – John Jun 18 '13 at 12:31
  • That'e exactly why my provider said, word by word :) – Jerry Jun 18 '13 at 13:15
  • I promise - I don't work for your provider. Nor have I ever worked for an ISP company. (At least not one that knew it was an ISP, but that's a different story.) – John Jun 18 '13 at 13:33
  • Thanks for help. I added 4GB memory, i'll see how it goes. – Jerry Jun 18 '13 at 13:47

It depends, start with more memory (significantly more to be honnest) once you are at the max of what your provider can offer you for a VPS, add another VPS. You can then loadbalance between these instances. Also on a side note, make sure your disks can keep up, I/O is a common bottle neck with VPS.


Configure all your services correctly so that they can't end up using all your RAM....

Apache: Configure mpm-prefork and fit the values to your needs

MySQL: configure all the buffers (InnoDB buffer pool, keybuffer.....) and max threads correctly.

It's going to take some time to find a perfect match - every setup is different. But in the end you can get the max performance out of your environment.

(nevertheless you can still throw hardware to your problem... ;) )

  • I disabled Billing Modules for plesk and Java modules, I hope that will help. Guide from this kb.parallels.com/en/9327 – Jerry Jun 18 '13 at 13:17
  • I'll run some RAM improvements, I'm already tired of this issue. Thank you. – Jerry Jun 18 '13 at 13:48

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