Best Practices for SAP BI using DB2 9 for z/OS - IBM Redbooks

7 x 24 application availability
99.999% database reliability offers resilience to unplanned outages. Such
database availability requires:
► A robust operating system. z/OS has more than one million lines of recovery
code, and has been evolving since 1966.
► Reliable hardware with internal redundancy and error correction logic. z/990
has a mean time to failure (MTF) greater than 30 years.
► That a processor continues to operate after the loss of an engine.
► That there is no single point of failure (SPOF). This support is provided by
Parallel Sysplex® with DB2 Data Sharing.
► Coupling Facilities, which fully support structure duplexing and automated
takeover.
► Reliable DBMS. DB2 has been evolving for more than 20 years and has been
stress-tested by more than 8,000 of the largest companies in the world.
► Dynamic CPU sparing. At a minimum, one of the z/Series processing units is
designated as a spare. If a running CPU chip fails and the instruction retry is
unsuccessful, the spare processing unit begins executing at precisely the
instruction where the other failed.
► Activation of the spare is done completely by the hardware, enabling the
system to be restored to full capacity in less than one second. Because most
hardware failures requiring repair will not cause an outage at the time of
failure or at the time of repair, the IBM System z achieves near-zero outage
for unplanned hardware repairs.
► Minimal planned outages. This is also known as continuous operations:
– Parallel Sysplex, coupled with DB2 Data Sharing and SAP Sysplex
Failover, allows rolling maintenance and upgrades of hardware, z/OS, and
DB2 without an outage.
– DB2 Online Utilities eliminate database maintenance, which is the leading
cause of planned outages in a UNIX® or Windows® environment.
– All of this is further complemented by hot-pluggable features, including
capacity on demand of System z and z/OS.
Capacity and scalability
Using a System z means that you have both vertical and horizontal capacity and
scalability:
► Vertical growth is achieved through more or faster engines in a single
symmetric multiprocessor (SMP) — the traditional growth path for UNIX and
Windows.
Chapter 1. Introduction 5