9.3.3 Write Record Caching (Quickwrite)

Write record caching, called quickwrite, extends the benefits of DFW to data that does not have a read-before-update access pattern (which is currently required to have a DFW hit) and for data with a poor cache hit rate. Data with a predictable record format, such as VSAM records, can benefit from this algorithm.

9.3.4 Sequential Caching

Sequential access to data is managed by a sequential caching algorithm that prestages tracks ahead of the record requested by the application. Once accessed, the space occupied by those tracks is marked as available for reuse rather than being subjected to the LRU algorithm (the exception is the 3990 controller). DB2, through the Media Manager, by requesting sequential caching, optimizes the cache management for better performance.

9.3.5 No Caching—Bypass Cache

Applications that do not benefit from caching can specify the bypass cache option in the Define Extent command. This setting is accomplished by the access methods. Most of the storage servers implement bypass cache by caching the tracks of data anyway, but also managing LRU algorithms for a faster reutilization of the cache space memory those tracks occupy.

9.3.6 No Caching—Inhibit Cache Load

A variant of bypass cache is the inhibit cache load (ICL) command. This command specifies that if the data is found in the cache, it can be read from the cache, but if not, it should not to be staged into the cache. This may be of benefit when the same data is accessed in several different modes, for example, read by a sequential prefetch operation as well as a random read operation.

9.3.7 DB2 Cache Parameters (DSNTIPE)

DB2 interfaces I/O through the VSAM Media Manager and uses the ICL command to optimize the sequential processes. The setting is done at DB2 installation time in the DSNTIPE panel. For the best large cache utilization, we recommend the SEQUENTIAL CACHE parameter being specified to SEQ (instead of default BYPASS) for DB2 prefetch. The UTILITY CACHE OPTION parameter should be set to YES (instead of default NO).

9.3.8 Dynamic Cache Management Enhancement

Dynamic Cache Management Enhanced (DCME) is an interactive cache resource management algorithm between System Managed Storage (SMS) and storage server Licenced Internal Code (LIC). SMS specifies for each data set the level of performance required:

•Whether the data set should be cached (must cache)

•Whether the data set should be excluded from caching (never cache)

•Whether caching should be used only if it is suitable to do so (may cache)

The recommendation is to define all data sets requiring performance as must cache (which is accomplished when an ACS routine sets them in a Storage Class defined with a low response time). This means that while all data sets use caching, the must cache data sets have an optimized LRU algorithm, which

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IBM 5655-DB2 Write Record Caching Quickwrite, Sequential Caching, No Caching-Bypass Cache, No Caching-Inhibit Cache Load
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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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