Linux Cluster High Availability Solutions

LifeKeeper for Linux is SteelEye Technology's easy, flexible, and fast solution for high availability.

Today many businesses struggle to balance the need for systems that can support mission-critical applications and pressures to reduce total cost of ownership for IT infrastructure. SteelEye's Linux data protection solutions enable businesses to get the best of both worlds - Linux cluster high availability.

Linux provides a high performance, reliable, open-source solution and its low cost makes it the platform of choice for companies that are targeting the new Web economy. SteelEye enhances the stability and power of Linux with LifeKeeper - a commercially proven, high availability Linux data protection software solution that provides fault-resilience to support mission-critical applications.

High Availability on Linux

SteelEye's LifeKeeper for Linux is a software application that ensures the continuous availability of applications by maintaining system uptime. LifeKeeper maintains the high availability of Linux cluster systems by monitoring system and application health, maintaining client connectivity and providing uninterrupted data access regardless of where clients reside - on the corporate Internet, intranet or extranet.

To enable automatic system and application recovery if the system goes down, LifeKeeper allows applications to failover to other servers in the Linux cluster. This helps LifeKeeper minimize the risk of a single point of failure and allows Linux systems to meet the stringent availability requirements of mission-critical operations by creating a fault resilient environment.

LifeKeeper for Linux works on both physical servers and virtual machines.

Fault Resilience

LifeKeeper provides fault resilience for Linux cluster environments by enabling other servers in a cluster to take over for failed servers or failed applications. Total cost of ownership is reduced, because LifeKeeper supports an active-active and N+1 server configurations. These models eliminate the need for extra servers dedicated for hot backup and allow clients and applications to failover to other production servers in the cluster.

Proactive Protection

With LifeKeeper, hardware component or application faults are detected in advance of a full system failure through multiple fault-detection mechanisms. LifeKeeper provides Linux data protection by monitoring Linux clusters using intelligent processes and multiple LAN heartbeats. By sending redundant signals between server nodes to determine system and application health, LifeKeeper confirms a system's status before taking action. This reduces the risk of a single point of failure and minimizes false failovers.

Lifekeeper for Linux Normal N+1 Configuration

While LifeKeeper is very adept at monitoring and protecting the systems hardware, SteelEye has long known that applications are the most critical element in a highly available system. LifeKeeper monitors applications to insure that they are alive and healthy. LifeKeeper also limits unnecessary failovers by recovering failed applications locally, without a full failover to another server, if the hardware is still active.

Lifekeeper for Linux N+1 Configuration Database Server has Failed

Transparent Failover

If an event creates an interruption in a server's availability, LifeKeeper automatically moves the protected resources and applications to another server in the Linux cluster. Because this switchover is transparent to clients, a system failure does not impact users' productivity. LifeKeeper migrates all applications and transfers connectivity in such a way that clients have continuous access to applications and data. This ensures that all clients - from internal users to customers shopping online - are not affected by unanticipated system failures.

Data Access and Integrity

In the LifeKeeper shared-storage environment, data storage is separate from the servers in the cluster. All data is stored on a shared disk array. This independence allows data to be accessed regardless of which server is being used to host the application. Additionally, LifeKeeper's shared storage locking mechanism helps maintain data integrity by locking the drive so that only one application can access specified data at one time.

LifeKeeper for Linux is a resource driven clustering system. This means that it is not tied to a quorum disk or system, thus providing a very flexible storage model. LifeKeeper for Linux can also use data replication or network attached storage for storage of critical application data. This provides the system architect the ultimate in flexibility when designing a highly available system.

Recovery Operations

LifeKeeper provides Linux data protection by supporting disaster tolerance, multiple system failures or faster recovery, including:

Shared Data Support

LifeKeeper for Linux provides for an N+1 configuration in all of its data models. Clusters constructed with shared storage (via SAN or iSCSI), multi-node data replication, or network attached storage can be configured to allow for a single back up system to provide protection for multiple critical systems.
Cascading Failover

LifeKeeper for Linux allows cascading failover for as many as 32 active nodes to ensure continuous client access in the event of system or application failure.

Application Recovery Kits

SteelEye offers LifeKeeper Application Recovery Kits for packaged software, including databases, Web servers and application servers. These Application Recovery Kits include tools and utilities that allow LifeKeeper to manage and control a specific application. When an Application Recovery Kit is installed for a specific application, LifeKeeper is able to monitor the health of the application and automatically recover the application if it fails.

SteelEye also provides the LifeKeeper Extender that supports the development of custom Application Recovery Kits. The Application Recovery SDK offers a powerful framework for developing customized recovery routines for proprietary applications as well as commercial application servers. Using SteelEye's Application Recovery SDK, special recovery routines can be defined by assembling straightforward application recovery scripts.

Uptime During Maintenance and Upgrades

LifeKeeper enables continuous operations during planned downtime for maintenance or upgrades as well as in the event of a system failure or if an application ceases to respond. The fault-resilient capabilities of LifeKeeper can be leveraged to facilitate system or application upgrades. With LifeKeeper, the amount of downtime required for common maintenance tasks and upgrades is significantly reduced or eliminated.