Cloud computing vs. Cluster computing

Cloud

Real servers

• Boot from local disk or PXE
• Install from FAI / CFengine
• Update/Upgrade via CFengine
• Only a very small Linux installation
• Pacemaker to move virtual servers
• Cluster file system (GFS, OCFS2, Ceph)
• Xen or KVM kernel modules and userland tools
• Routing tables

Virtual servers

• Xen or KVM images
• Boot very fast
• Simple to backup
• New or upgraded server images can be cloned and / or auto-configured by templates
• Reside on cluster file system
• Never store user data on vservers
• Store user data (plain file, database etc.) on shared / shareable disk