IBM zSystems architecture and the z/OS operating system
The z/OS operating system is highly secure, scalable, and open, and it offers high-performance that supports a diverse application execution environment. The tight integration Db2 has with IBM zSystems architecture and z/OS creates a synergy that allows Db2 to exploit advanced capabilities in the operation system and hardware.
The z/OS operating system is based on 64-bit IBM zSystems architecture, and Db2 13 for z/OS operates on the following hardware and software: | Hardware: | IBM System zEC12 or later |
|---|---|
| Operating system: | z/OS 2.4 or later |
| Other software: | IRLM 2.3 running at function level 3.050 or later You can use the following command to determine the IRLM function level: |
Db2 gains a tremendous benefit from IBM zSystems architecture. The architecture of Db2 for z/OS takes advantage of the key 64-bit virtual addressing support. With 64-bit IBM zSystems, Db2 gains an immediate scalability benefit.
The following IBM zSystems features benefit Db2:
- 64-bit storage
- Increased capacity of central memory from 2 GB to 16 exabytes eliminates most storage constraints. 64-bit storage also allows for 16 exabytes of virtual address space, a huge step in the continuing evolution of increased virtual storage. In addition to improving Db2 performance, 64-bit storage improves availability and scalability, and it simplifies storage management.
- High-speed communication
- HiperSockets enable high-speed TCP/IP communication across partitions of the same IBM zSystems server, for example, between Linux® on IBM zSystems and Db2 for z/OS.
- Dynamic workload management
- The z/OS Workload Manager (WLM) provides solutions for managing workload distribution, workload balancing, and distributing resources to competing workloads. z/OS workload management is the combined cooperation of various subsystems (CICS®, IMS/ESA®, JES, APPC, TSO/E, z/OS® UNIX System Services, DDF, Db2, LSFM, and Internet Connection Server) with z/OS workload management. The Intelligent Resource Director (IRD) allows you to group logical partitions that are resident on the same physical server, and in the same sysplex, into an LPAR cluster. This gives Workload Manager the ability to manage resources across the entire cluster of logical partitions.
- Specialty engines
- With special processors, such as the IBM z Integrated Information Processor (zIIP), Db2 achieves higher degrees of query parallelism and higher levels of transaction throughput. The zIIP is designed to improve resource optimization and lower the cost of eligible workloads, enhancing the role of the mainframe as the data hub of the enterprise.
In addition to the benefits of IBM zSystems architecture, Db2 takes advantage of many other features of the z/OS operating system:
- High security
- z/OS and its predecessors have provided robust security for decades. Security features deliver privacy for users, applications, and data, and these features protect the integrity and isolation of running processes. Current security functions have evolved to include comprehensive network and transaction security that operates with many other operating systems. Enhancements to the z/OS Security Server provide improved security options, such as multilevel security. The IBM zSystems environment offers highly secure cryptographic functions and provides improved Secure Sockets Layer (SSL) performance.
- Open software technologies
- z/OS supports the latest open software technologies that include Enterprise JavaBeans, XML, and Unicode.
- Cluster technology
- The z/OS Parallel Sysplex® provides cluster technology that achieves availability 24 hours a day, 7 days a week. Cluster technology also provides the capability for horizontal growth. Horizontal growth solves the problems of performance overheads and system management issues that you typically encounter when combining multiple machines to access the same database. With horizontal growth, you achieve more scalability; your system can grow beyond the confines of a single machine while your database remains intact.
- Solid-state drives
- Solid-state drives (SSDs) are more reliable, consume less power, and generate less heat than traditional hard disk drives (HDDs). SSDs can also improve the performance of online transaction processing. SSDs are especially efficient at performing random access requests, and they provide greater throughput than HDDs. Some IBM® System Storage® series allow a combination of HDDs and SSDs.
- Parallel Access Volume (PAV)
- IBM Enterprise Storage Server® (ESS) exploits the Parallel Access Volume and Multiple Allegiance features of z/OS and supports up to 256 I/Os per logical disk volume. A single z/OS host can issue I/Os in parallel to the same logical volume, and different hosts can issue I/Os to a shared volume in parallel.
- HyperPAV
- HyperPAV is available on some IBM System Storage series. HyperPAV helps applications to achieve equal or greater I/O performance than the original PAV feature, but uses fewer z/OS resources.
- Adaptive multi-stream prefetching
- Adaptive multi-stream prefetching (AMP) is a sequential prefetching algorithm that resolves cache pollution and prefetch waste for a cache that is shared by multiple sequential request streams. AMP works well to manage caches efficiently across a wide variety of workloads and cache sizes.
- Cache optimization
- Db2 code and control structures are adapted to reduce cache misses.
- MIDAW
- The IBM zSystems environment also supports the Modified Indirect Data Address Word (MIDAW) facility, which is designed to improve channel utilization and throughput, and which can potentially reduce I/O response times.
- FICON® channels
- These channels offer significant performance benefits for transaction workloads. FICON features, such as a rapid data transfer rate (4 GB per second), also result in faster table scans and improved utility performance.
- High performance FICON
- High Performance FICON (zHPF) is a new FICON protocol and system I/O architecture which results in improvements for small block transfers to disk using the device independent random access method.
- IBM zSystems instructions
- Db2 can take advantage of the latest IBM zSystems instructions. These instructions can streamline specific processes and reduce the CPU workload.
- Increased IBM zSystems page size
- Db2 benefits greatly from the 1 MB page size of IBM zSystems hardware. The increased page size allows for Db2 buffer pool enhancements which can reduce the CPU workload.
- Improved hardware compression
- Improved hardware compression has a positive impact on performance. For example, utilities that run against compressed data run faster.