Issue #16 February 2006

Delivering application and services availability

by Subbu Krishnamurthy

The need for application and services availability in an environment where data needs increase daily is a challenge for every IT manager. Managers are now faced with security issues, horizontally scaling infrastructure, accelerating storage demand, and the need to port critical applications to Linux® and open source.

A few of the constant issues also faced by IT managers are finding ways to reduce costs in the infrastructure, improve manageability, and deliver better and more timely services to their constituents.

Is there a way to leverage the commoditization of servers while lowering storage management costs to deliver the level of application and services availability being demanded?

Today, the answer is yes. Red Hat and HP have combined to deliver a highly available, manageable, and scalable solution. Combining HP Serviceguard for Linux (SGLX) and the Red Hat® Global File System (GFS) provides the benefits of shared storage beyond the basic capabilities of storage consolidation, server aggregation, and storage networking. Red Hat GFS, a native, 64-bit cluster file system, extends the benefits of shared storage by enabling concurrent read/write access from multiple servers while HP Serviceguard for Linux delivers the services and application fail-over ensuring high availability from the data layer to the application layer.

Working jointly, HP and Red Hat have devised an end-to-end solution to make business applications and data constantly available in a cluster of HP servers running Red Hat Enterprise Linux. HP Serviceguard for Linux creates a cluster of Linux servers that make applications and services available despite hardware or software failures or planned downtime. The targeted customer applications include web services, NFS services and custom application services.

Some of the key applications for deployment include:

Fig 1. Web services
Fig 2. File services (NFS)
Fig 3. Database services

HP Serviceguard for Linux

HP Serviceguard for Linux is high-availability clustering software that groups servers, or nodes, to provide redundancy and enable constant access to the applications on those servers. HP Serviceguard for Linux puts all the resources needed to run an application into a flexible package, which it then uses to start, halt, move, or fail-over the application. With the application resources now being managed by HP Serviceguard for Linux--instead of by the operating system on the server--use of the application is not tied to any one server. The application can be moved among the servers for planned downtime, such as maintenance, with no disruption of application services to the users.

HP Serviceguard for Linux can respond to single or multiple failures within a cluster and is designed to protect applications from a wide variety of software and hardware failures. It monitors the health of each server or node and quickly responds to failures in system processes, system memory, LAN media and adapters, and application processes. Using software techniques and multiple hardware paths to keep an application running on the same node, HP Serviceguard for Linux only fails-over and restarts applications to another node as a last resort, further helping to minimize unplanned service disruptions.

The HP part number for the new bundled offering from HP is T2798AA#001, for a one year subscription. Support for Red Hat Global File System on the servers is provided by Red Hat at the same (Support Level Agreement (SLA) as purchased for Red Hat Enterprise Linux. A cooperative support agreement exists between HP and Red Hat that ensures the smooth handling of all support questions for customers.

Red Hat Global File System

Red Hat GFS enables servers to share files via a common SAN file system. Normally, only one server in a SAN has access to a disk or logical volume at a time. Red Hat GFS creates a common file system across multiple SAN disks, or volumes, and makes this file system available to multiple servers in a cluster. By eliminating the need for multiple copies of data, Red Hat GFS increases performance, reduces management complexity, and lowers costs with consolidated storage resources.

Red Hat GFS protects data integrity by coordinating access to a file so that reads and writes are consistent between servers. It also improves availability by making the file system accessible to all servers in the cluster. If there is a failure in the cluster that causes an application to be moved from one server to another, the file system is immediately available to the application in its new location.

Better together

Together, Serviceguard and GFS provide continuous access to both applications and services and data, and the ability to scale out without compromise. Serviceguard uses software techniques and multiple hardware paths to keep applications & services operating on the same node. If a node fails, Serviceguard restarts the workload on another node and Red Hat GFS serves up the same data via an alternate node with the same system view. Serviceguard and GFS are best-of-breed clustering technologies for Linux, working together as a comprehensive high availability clustering solution from the applications to the data. On February 6th, HP launched a specially priced, bundled offering that includes HP Serviceguard for Linux with Red Hat GFS.

For more information

To find out more about clustering solutions from HP and Red Hat, visit:

About the author

Subbu Krishnamurthy is a Senior Product Marketing Manager.