Differences between Virtual Private Servers and Dedicated Servers

This article describes the differences between a Linux VPS and a Linux Dedicated Server from the perspective of Linux system administration and basic functionality. The information presented here is not all-inclusive, nor will the technology behind these differences be discussed.

Linux system administrators seeking a comprehensive guide to their virtualization platform of choice should consult the OpenVZ Documentation or Xen Documentation.

Contents 1 Fundamental Differences 1.1 Kernel and Hardware Differences 1.2 Network Interfaces and Hostname Reset on Reboot 2 OpenVZ Platform-Specific Differences 3 Xen Platform-Specific Differences

Fundamental Differences

The following differences can be noted on either the OpenVZ or Xen virtualization platforms:

Kernel and Hardware Differences

• Modified kernels are not supported at VPSLink
• All hardware is virtualized - Hardware clock may not be modified

Hardware clock workaround: VPSLink runs NTP on all hardware nodes to ensure server time is reported accurately. Setting the Linux System Timezone is a reliable way to synchronize your VPS time with your local time.

Network Interfaces and Hostname Reset on Reboot

• Network interface changes are reset when the VPS is rebooted
• Server hostname is reset when the VPS is rebooted

Configuration reset workaround: Add configuration commands to your /etc/rc.local file to reconfigure your VPS whenever it is booted.

OpenVZ Platform-Specific Differences

• C libraries may not be modified on OpenVZ
• Resolver nameservers are reset on reboot

Any allocations in excess of your VPS memory limit (RAM) will result in processes being killed on OpenVZ - please see the Problem: Process or Daemon Dies article for more information on OpenVZ's behavior and troubleshooting.

Xen Platform-Specific Differences

• C libraries may not be modified on Xen unless the modification is performed on a non-thread local copy of the compiler
• Root password may be reset on domain reboot

Note: The root password reset issue has been tracked to a system administration tool used by the VPSLink support and system administration teams. VPSLink's standard operating procedure will be modified to work around this issue in the future.