I recently moved my site from a shared hosting to a VPS.
When it was in the shared hosting, actually nothing went wrong, but now, the VPS server became unresponsive 4 times in 2 weeks (and I need to reboot it).
I thought VPS would be more stable and could handle more traffic, how come my previous shared hosting seems better in my case?
When the VPS becomes unresponsive, I mean I can ping it, but I cannot ssh into it, and the worse part is that the web pages cannot be loaded. Nothing wrong shows in /var/log/message. I don't know the real cause for this problem, but I guess it's the amount of traffic?
My VPS is configured with 2 CPU with 4GB RAM in CentOS. According to the host, the VPS machine is Dell & Supermicro E5-2600 (6 cores CPUx2) with 128G RAM & SAS 15k RPM+RAID6 HD. And my site has 4000-6000 page views per day in average. I don't know why the shared hosting can handle it well but the VPS can't.
How to decide if current VPS problem is due to the traffic? Is something wrong with the VPS provider? Or the hardware is not good enough to handle such "medium" traffic? How to determine the hardware/configuration of a VPS to handle the traffic I am having (and to handle the future traffic I am expecting, which might have a jump because of my coming service release).
Any thoughts or experience sharing are appreciated. Thanks.