| Craig S. Mullins
Database Performance Management
Craig S. Mullins
At this stage of the game there can be no doubt
that Internet usage is becoming pervasive. Every business is being
impacted by the rapid adoption of Internet technologies. Indeed, a new
term, e-business, has been coined to describe the changing nature of
business when it is conducted online over the Internet and the World
An e-business is always online; it never
closes. Regardless of the time or date, customers expect an e-business
to be up and running, available to serve their current needs. Whether
e-business customers expect e-commerce, online investing, news and
information, or simply to comparison shop, full functionality and
availability 100% of the time is expected. Why should customers wait
for an unavailable e-business site to become available again? They
won’t because numerous competitors are just a simple mouse click
For these reasons, an e-business must be
available and operational 24 hours a day, 7 days a week, 366 days a
year (don’t forget that extra day in leap years!). An e-business
must be prepared to engage with customers at any time or risk losing
business to a company whose web site is more accessible. So
availability for an e-business becomes an even higher form of
availability, let’s call it e-vailability TM. System outages, whether planned (for
maintenance and tuning) or unplanned (due to hardware failure, bugs,
or viruses), are the enemy of the successful e-business.
So it stands to reason that those who manage
the IT infrastructure for an e-business must be alert and
proactive—ensuring that the e-business maintains the highest degree
of availability possible.
Companies functioning as e-businesses will find
their applications and IT infrastructure becoming incredibly complex.
Complexity is nothing new for the IT professional, but the needs of an
e-business cause the level of complexity to expand enormously. The IT
shop of an e-business will quickly find themselves needing to
implement, maintain, and manage integrated systems consisting of
traditional and legacy systems coupled with web-based technologies. A
key component of these applications will be access to and storage of
mission-critical data. And the most reliable, time-tested method of
storing persistent data is inside a database.
When databases are involved, DBAs are required
to implement them, optimize performance, and to ensure high
availability. This is the traditional role of the DBA. This role is
greatly expanded and becomes more difficult for the e-business.
When an outage threatens availability, the eDBA
needs to be armed with tools to eliminate or minimize the outage. It
can be difficult, if not impossible, to avoid outages using
traditional technology and tools. Consider, for example, what needs to
be done when storage space needs to be increased. Imagine an
e-business that experiences abnormally high transaction workload over
the holiday season. Perhaps online shopping was projected to grow 150%
over last year, but instead it grows 250%. This means more users, more
data, and more programs running. To adjust to the expanded workload,
an eDBA may need to dynamically alter buffer pools, program storage
area (e.g. EDM pools), and sort work area. But most database servers
must be stopped and re-started to change these parameters. What needs
to be done?
The eDBA should have tools at his disposal to
work around the limitations of the DBMS. For example, BMC Software
offers Opertune to change DB2 parameters “on the fly,” without the
cycling DB2 subsystem. So, as an eDBA, you could expand the EDM Pool
and maybe add more archive logs without bringing your system down.
This increases availability by eliminating outages.
However, not all outages can be eliminated.
Consider a faulty memory chip or disk drive. No one can predict when
hardware fails. Certain failsafe methods can be implemented with
redundant storage or automatic propagation of changes to a mirrored
system. But at some point, due to some problem or disaster, a problem
can still occur causing an outage.
If this is the case, the eDBA needs to be prepared to recover
as rapidly as possible. This
reduces the time of the outage that can not be eliminated.
Using tools such as BMC’s Recovery Manager, Recover Plus,
Copy Plus, and SQL BackTrack, eDBAs can quickly recover databases
after unplanned outages. The time of the outage can be minimized
because tools such as these can be used to automatically build
recovery scripts and then recover faster than traditional recovery
The biggest challenge for the eDBA is data
availability. If data is
not available, the e-business is not functioning.
This will impact sales, profitability, and ultimately stock
price and valuation. Being prepared to eliminate and reduce planned
and unplanned outages is the biggest job of the eDBA.
Of course, there are other technological differences in the job
of an eDBA versus a traditional DBA.
Keep watching this space in future issues of Database Trends
for more details on the duties of an eDBA.
Note: e-vailability is a trademark of BMC Software.