Operating Systems

The introduction of Linux on System z in 1990 provided many new options for z/VSE customers, including access to many applications that can run side-by-side with Linux applications in the same System z box. Effective, high-performing z/VSE Connectors to Linux applications made Linux on System z a natural extension of z/VSE into an open environment. Linux on System z enhances z/VSE, offering the best of both worlds—an open, scalable platform with the stability and reliability of System z. 

The z/VSE community quickly embraced these new capabilities; Linux on System z became a mature environment that helped z/VSE customers modernize their systems. Today, as customers in all industries pursue system optimization and enterprisewide data management, they’re finding Linux on System z useful for business-critical applications and processes. It’s often used as the main Web entrance to the enterprise and as a centralized data store—with z/VSE applications and data integrated via Connectors and Service-Oriented Architecture (SOA) components. 

For heterogeneous environments with a high quantity and diversity of data (common at z/VSE sites today), Linux on System z is a good choice for a centralized database and data warehouse. z/VSE applications can interoperate well with Linux on System z and relational data in DB2. 

Strategic decisions can be made more effectively when they’re based on complete, accurate operational data, so a unified, common data store for different data sources is critical. An enterprise data management architecture that supports a flexible global view of the business meets that requirement, facilitating faster and better decisions. 

Data centralization can be implemented in a logical or physical manner. Logical centralization can be supported using a virtual database that can access different physical databases on distributed environments, on z/VSE or z/VM. A single virtual database enables relational queries to multiple, different distributed data entities in the same query statement. Logical consolidation can be the first step toward physical integration of the data into one big Linux on System z database. 

Physical integration or rehosting of the database can improve the efficiency of data processing and analysis. IBM System z and DB2 for Linux on System z can handle large enterprise databases. A single enterprise data pool to manage, back up, and analyze data can provide many advantages. Consolidation of databases from distributed platforms reduces database and hardware environment complexity. DB2 on Linux on System z can be useful for consolidating data from DB2 Server for VSE and DB2 Server for VM or other DB2 databases in distributed environments 

Figure 1 shows a common data store. Here, a data warehouse is used to consolidate the data and a Business Intelligence (BI) tool is used to accommodate analysis and decision support.

To help z/VSE customers use Linux on System z to create a DB2 environment, we created an IBM Redbook titled z/VSE Using DB2 on Linux for System z (SG24-7690), which is available at www.ibm.com/redbooks). The Redbook covers: 

  • How to plan, install, and build a DB2 environment on Linux on System z
  • Advantages of enterprise data management and how to achieve them using Linux on System z
  • Business and implementation considerations for integration with the existing environment. 

     Here’s a summary of some key information from the Redbook: 

Planning: Start with a detailed plan of the new environment and determine how a virtualized environment with z/VM can support future needs. Consider the specifics of your disk environment, the connectivity of System z to the disks, and placement of the data in the disk subsystem. Plan for data integration by considering data types and the platforms on which your data resides. Remember that network topology is flexible in a virtualized environment with z/VM. Your z/VSE applications can access the Linux environment using DB2 Server for VSE or VM client edition. 

Setup: To set up Linux on System z and DB2 in Linux on System z for a production environment, start with an existing DB2 environment in z/VSE and enable a DB2 client in z/VSE or z/VM so applications can access data in Linux on System z. You can do this using the application requestor function in DB2 Server for VM and VSE or with the DB2 Server for VSE client edition. For a logical consolidation of data, you need to define the federated database that represents the central virtual database that all applications will access. This database has pointers to the individual physical databases and tables in DB2 VSE, DB2 VM, and distributed databases. 

DB2 data migration and application dependencies: For existing applications on z/VSE or z/VM to access the database on Linux on System z, you must move the data to the new database on Linux on System z. This is a first step for rehosting the database. The data can be unloaded from DB2 in z/VSE and reloaded into DB2 on Linux on System z. A better approach is to use the federated database in Linux on System z and move the data using an SQL cursor that reads from DB2 VSE and inserts it into DB2 on Linux on System z. You also need to migrate or regenerate the database packages and the package authorizations the DBMS uses to access data. This occurs by compiling and binding the VSE applications with access to DB2 on Linux on System z. That will produce the DB2 access packages in DB2 on Linux on System z for all requests. 

Before moving into production, conduct a parallel run with the old and the new environments. You can do this using the DB2 replication feature to keep the DB2 databases synchronized. 

Monitoring and tuning: Monitoring and tuning are necessary for optimal performance and can be measured in terms of system response time, throughput, and resource utilization. By examining these factors, you can see which parts affect the resources and system and how well those resources are used and shared. You can use built-in tuning methods or purchased tools to examine the impact the different layers or subsystems have on performance; these can help you identify and resolve possible bottlenecks. 

Today, key business applications must be available continuously and that often requires using Internet technologies. Your Web-based global business platform must be secure, reliable, and available. Linux on System z enhances z/VSE and creates a 24x7 environment that scales as needed and provides the stability and reliability of System z.