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IIS: Haute disponibilité et PRA IIS and SQL Server form the hub of many e-business websites. LifeKeeper IIS solution works seamlessly with SQL Server to maintain maximum uptime of e-business websites.
Real-time replication of website data over a LAN or WAN
Replication is real-time and can be synchronous or asynchronous. Replication can be to multiple targets making a 3-node solution with a local and remote backup possible.
Monitoring and automated recovery of IIS Services
The LifeKeeper IIS Recovery continuously monitors the health of Internet servers, and if a problem arises, provides automatic failover of the affected web service to a standby system. The Recovery Kit protects Web, FTP and SMTP services of IIS , Multiple Web, FTP or SMTP sites can be stopped/started independently.
Virtual solutions
All the solutions given here work both in physical and virtual environments, with or without shared storage.
The IIS Recovery Kit protects Internet servers from the following problems:
• System failure or server shutdown
• Network Interface Card (NIC) failures
• Communication failures (Web server is running but stops responding)
• Start-up failures (Web server aborts on start-up)
2-node solutions
LifeKeeper can be configured to run in an Active/Active (or Active/Backup) configuration. With or without shared storage, over a LAN or a WAN. The image below illustrates an Active/Active environment, where each server, under normal circumstances, is active - but also acts as a backup to another. This approach allows for maximum hardware utilisation, and removes the need for redundant backups.
Recovery scenario of IIS
The IIS Recovery has two recovery procedures. For system or NIC failures, the Recovery transfers the affected web server’s resources to a standby system, and then starts up the standby web server. If there is a communications or start-up failure, and local recovery is enabled, the IIS Recovery Kit will first stop and restart the affected web server to see if that corrects the problem. If the restart is unsuccessful, it will transfer IIS services to the backup web server.
LifeKeeper’s IIS recovery manages the dependencies between the IIS application, IP and volume resources.
Configuration and setup of an IIS server under LifeKeepers control is a relatively straight forward process, and supports virtual hosting if required.
Failback of IIS servers
Once a failover occurs and the system has been recovered, data is resynchronised backwards to the previously live server. When the data resynchronisation is complete, the system can be returned to service without any further disruption to the users. Bandwidth is used effectively due to data replication features which allow compression of data.
3-node solution
The ability to replicated to multiple servers means that it is possible to have a 3-node solution which provides for a local and remote backup. In the example below, there is a local SQL Server and an IIS server, both servers are used as local backup for each other. Remotely, there is only one server which acts as a disaster recovery for either or both servers.
Multi-node solutions
As well as the Active/Active configuration it is possible to have an N+1 configuration, where N machines are active, and 1 machine acts as a standby to all of them. This allows for better performance in the event of a single failover, as a single machine will not be doing the job of two.
Virtual solutions
Al the solutions given here work both in physical and virtual environments, with or without shared storage.
Source: Open Minds (http://www.openminds.co.uk) | |
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