Installations having these devices could use sequential caching as an installation option. Installations with a mixture of devices with large, small, or no cache can benefit from the bypass cache option.

2.2.3 Log Structured File

Devices using the log structured file technique (like the RVA) do not maintain data location during data updates. For these devices there exists a concept of logical location of data, independent from the the physical location. The logical location is used by the device to present the data to the application: the user sees a contiguous extent on a 3390 volume, while the data is in reality scattered across the LSF.

A REORG of a DB2 table space provides a logical sequence of records which could not be corresponding to a physical sequence. This is a function of the space management of the storage server.

Worrying about reorganizing data to reclaim space extents is now much less critical with the new disk architecture. REORG does not need to be run in order to reclaim fragmented space in this case, only to reestablish the clustering (logical) sequence and the DB2 internal free space. When the DB2 optimizer chooses sequential prefetch as a valid access path, the storage server detects the logical sequential access and initiates pre-staging of the logically sequenced tracks into cache, providing improvement to the I/O response time for the subsequent prefetch accesses.

2.2.4 RAMAC Architecture

Disk architecture defines each volume in a logical way through tables. These tables do an effective mapping between the logical view of the volume onto the disk array with data and rotating parity physical disks. This means that each I/O operation takes place to or from several physical disks. However, the host still views only the logical volume topology, and it bases its optimizing and scheduling strategies on this view, as it used to do with native 3380 and 3390.

2.2.5 SMS Storage Groups

Volume separation is easy when you have hundreds of volumes available. But this separation is good only if your volumes have separate access paths. Path separation is important to achieve high parallel data transfer rates.

Without DFSMS, the user is responsible for distributing DB2 data sets among disks. This process needs to be reviewed periodically, either when the workload changes, or when the storage server configuration changes.

With DFSMS, the user can distribute the DFSMS Storage Groups among storage servers with the purpose of optimizing access parallelism. Another purpose could be managing availability for disaster recovery planning. This can be combined with the previous purpose by letting DFSMS automatically fill in these Storage Groups with data sets, by applying policies defined in the automatic class selection routines.

Changes to the topology of the Storage Group can be managed to minimize the application outages. This can be done simply by adding new volumes to the Storage Group, then managing the allocation enablement (opening it on new

Summary of Considerations 7

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IBM 5695-DF1, 5655-DB2 manual Log Structured File, Ramac Architecture, SMS Storage Groups
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5695-DF1, 5655-DB2 specifications

IBM 5655-DB2 and 5695-DF1 are significant components within the IBM software ecosystem, predominantly focusing on data management and integration solutions. These offerings cater primarily to enterprise environments that require robust database management systems and associated frameworks to maintain and manipulate data efficiently.

IBM 5655-DB2 is a well-known relational database management system (RDBMS) that excels in managing large volumes of structured data. Its architecture is designed to support high availability, scalability, and performance, crucial for businesses operating in today’s data-driven world. Some of its main features include advanced indexing capabilities, support for complex queries, and dynamic workload management. Additionally, it provides strong concurrency controls, which enable multiple users to access and manipulate data simultaneously without compromising data integrity.

One of the key characteristics of DB2 is its support for various data types, including JSON and XML, making it versatile for modern applications that generate data in diverse formats. It also features robust security mechanisms to protect sensitive data, aligning with compliance standards across industries. Integration with analytics tools further allows businesses to derive insights from their data, enhancing decision-making processes.

On the other hand, IBM 5695-DF1, also known as the InfoSphere DataStage, is a powerful data integration tool that facilitates the extraction, transformation, and loading (ETL) of data from various sources to target systems. It empowers organizations to streamline their data flows, ensuring that clean, consistent information is available for analysis and operational use. Key features of 5695-DF1 include a user-friendly graphical interface that enhances developer productivity and a rich set of connectors for numerous data sources, enabling seamless data integration.

DataStage also supports real-time data integration, allowing businesses to keep their data synchronized across multiple platforms. Its parallel processing capabilities dedicatedly optimize performance, enabling organizations to handle vast datasets efficiently. It incorporates data quality tools that help in validating and cleansing data before it is used for decision-making processes.

Both IBM 5655-DB2 and 5695-DF1 are part of a broader strategy to accommodate the evolving landscape of data management. Businesses leverage these technologies to enhance their data architectures, fostering agility and competitive advantage in their respective markets. Their integration capabilities, along with a focus on security and scalability, position them as vital assets in modern enterprise environments. Whether managing critical data within a database or ensuring seamless data flow across systems, these IBM offerings provide a comprehensive approach to handling complex data challenges.
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