Choosing the type of VPS

Basically, there is 2 type of VPS whether it is a VM, virtual machine or a VPS, they are virtualized. But if you are examing carefully, they could be different. The VPS is either virtualized by OpenVZ or the commercial licensed Virtuozzo, or Hypervisor like KVM. OpenVZ and Virtuozzo are the same types of virtualization. They are known as OS level virtualization while Hypervisor like KVM is a hardware level virtualization. In terms of usage, they are little differences but there are some restriction on an OS level virtualized environment as well as a con in like KVM full virtualization.

Let us begin,  the OpenVZ virtualization is like sharing CPU, memory and disk space dynamically. Although you are still catered to the resources you have purchased. Another word, you might use more if the server allowed but on other hands, you can be slower if your server has a lot of guest machines.  Many circumstances, an OS or a control panel files are shared using the template system. This is an advantage to the hoster, as this has greatly reduced the disk space used. And it has helped to speed up the deployment process if they are universal. You are not likely to customize it

OpenVZ uses host kernel. It’s not possible to install applications require kernel existence like Anti-Virus or Backup agent etc. However, the guest machines create instructions and make a call to the hardware directly, thus the overhead is lower and it is faster. Kernel updates might be an issue to address OS vulnerability if you do not use 3rd party solution like Kenerlcare on the host server. To take effect the changes, a reboot is required.

I prefer Hypervisor like KVM for these reasons; In a KVM guest OS is independent so the kernel. You can have a mix of OS guest machines not limited to the kind of OS installed on the host server. You can install any application, there is no such restriction like an OpenVZ VPS. No doubt KVM Full virtualization has higher overhead as their hardware is emulated and virtualization, however, these years there are improvements like ballooning and paravirtualization has improved a KVM guest machines.

If you are looking for better isolation and security. A hypervisor will do better in this area. This is one of the major reason why Vastspace has chosen KVM for our VPS plans.

Is SPF important?

SPF is a DNS record to tell other email servers that emails from the designated email servers are permitted. If emails are not originated from the mentioned email servers in the SPF, they are likely impersonated, not genuine or spam emails. At the end of the SPF statement, you will see these syntaxes – ~ ?, the common one is ~ follows by a like this ~a meaning ‘softfail’ marked the email and higher spam score if the email has violated SPF preset in the sender DNS record.

SPF is used to fight spam emails if the emails were sent from an unauthorized mail server with a probably compromised email account. It is easy to explain or interpret to a technical person. However, it is not the case for a non-tech person. For the last 20 years, I have seen many have sent emails using other email servers. These senders have more than 1 email account set in their email client application. Unknowingly, these senders sent out emails using another email server which is not authorized and eventually, the email is marked as spam or bounced.

SPF is effective to fight spam emails. But on other hands, an email can be marked as spam email mistakenly. I have mixed feeling on this. SPF set by the email server admin is used to fight spam emails, however, it can be a double-edged sword in this case. So, it is unsafe to use ‘-a’ but ‘~a’ softfail at least the email will not return in the event if the sender has used the wrong email server to send his or hers’ emails.


When you will need a VPS?

Many have asked the question, do I need a VPS? If you found yourselves in these situations, very likely you will need a VPS, a KVM VPS in specific.

  • I want to update my server OS kernel and reboot based on my schedule.
  • I do not want to share my services. I can restart if they are dead.
  • I want better isolation/ privacy. I do not wish to share my web content in the same environment.
  • I need one or more dedicated IP.
  • I need to root SSH to my server.

Why buy a VPS?

There are a few reasons why you should buy a VPS but not a shared Web Hosting.

  • if you want a full root shell access.
  • update a kernel fixes at your own timing (only possible with Kernel independent VPS like KVM)
  • hosts a few websites and full control with better management.
  • install the components or applications.
  • allocate unused resources.
  • restart services at your own preferences.
  • with a better budget.
  • better isolation.
  • dedicated IP address, it is optional in Shared Hosting.