Complex Hosting

We build and deploy complex hosting environments incorporating

• Load balanced web and application servers
• Database replication
• File system/storage replication
• Caching servers

We use do this using

• VMWare, Xen and KVM
• DRBD
• Heartbeat + Pacemaker
• Puppet

We do this across an extensive list of supported applications

• Two physical servers or virtual machines
• Web server on each host
• Application level content synchronisation
• Active/Passive or Active/Active configuration
  

• Entire operating system is replicated.
• Active/Passive mode.
• Passive VM is switched off, subject to boot duration at time of failover (~30 seconds)
• Independent of operating system and database type.
• Easiest implementation, least complexity but greatest disruption during failover.
• No application awareness required. Presents as a single server to the end user.
• Can be deployed on Linux or Windows.
  

• Same technology as virtual machine replication, except only the files required for the specific application are replicated.
• Active/Passive mode only.
• Passive application server (eg database) is switched off, subject to service load time at failover (~5-10 seconds)
• No application awareness required.
• Deployed using Heartbeat + DRBD
• Only supported on Linux
• Suitable for database or file system replication.
  

• Dependent on application level support
• Implementation modes dependent on support from application vendor.
• Highest degree of complexity, lowest failover time.
• Varying degrees of application level awareness required.