Today’s data warehouses are expected
to have much higher availability than
those of the past. No longer simply back-
end systems supporting a few power users,
data warehouses are now operational
systems that support hundreds, sometimes
thousands of users in their daily tasks.
Companies have come to realize just how
important their data warehouses are to
their businesses, not only for strategic
decisions but for daily tactical decisions as
well. Service disruptions to the data ware-
house can translate into serious disruption
to the organization.
As a result, a high level of continuous
availability to users is now a requirement,
and more and more companies are moving
to dual-system environments to ensure that
their service level agreements (SLAs) are
met. Additionally, companies employing
dual systems want to maximize the use of
both systems for production workloads,
which requires workload balancing and
system-to-system capacity adjustments.
With dual systems becoming mainstream,
it is important to have a product that allows
powerful yet simplified monitoring, admin-
istration and control of this environment.
Coordinating effortsIn a single-system environment from
Teradata, many tools allow administrators to
monitor the system’s status and take action
as necessary. Here, “system” is defined as a
set of coordinated servers, software and pro-
cesses that accomplish a common goal. The
same is true in a dual-system environment.
While each system runs independently of
the other, the goal of a dual-system environ-
ment from Teradata is to have coordination
between the two—and their supporting
servers and processes—to accomplish a
common goal of meeting pre-defined ser-
vice levels for availability and disaster recov-
ery. To achieve this level of coordination, the
systems must have these capabilities:
> Monitoring. The two Teradata systems
must be monitored along with their
supporting servers and processes;
in effect, the entire data warehouse
environment. This includes tracking
the operational state of each system/
server, the start/stop/completion status
of processes such as data loading and
the currency of data between the two
Teradata systems. It is important to
monitor these and other parameters to
understand whether a given system is
operational and has the required data
to service a query. Knowing what is
happening in the environment is essen-
tial before any action can be taken.
> Administration. Invoking changes to
query routing rules, for example, is
required to maintain SLAs for certain
classes of users. It does not matter
Power2
SERVICES
Teradata Dual Active Solution ensures a smooth ride. by Stan Mlynarczyk, Rick Stellwagen and Imad Birouty
PAGE 1 | Teradata Magazine | September 2008 | ©2008 Teradata Corporation | AR-5721
SERVICES
whether these changes
are manual or auto-
mated, as long as the
ability to administer
the changes exists.
> Control. A dual-
system environment
has the ability to start
and stop processes,
take a system down
for planned mainte-
nance or re-engage
a system after an
unplanned outage.
While monitoring,
administration and control
are described as distinct
capabilities, they are in
reality used in a coordi-
nated fashion to understand
what is happening within the dual-system
environment and, consequently, to take the
desired actions.
Automated managementTeradata Multi-System Manager is part of
the Teradata Dual Active Solution and, as
its name suggests, is designed to handle
multiple Teradata systems. The follow-
ing set of features enables coordination
between systems and allows an organiza-
tion to manage its data warehouse environ-
ment from a single console at the system
and application levels:
> A unified view of a multi-system
environment. A multi-system envi-
ronment includes supporting servers
for data loading, query routing and
applications. A central console enables
a view of the system’s status and key
Monitoring an application across two sites
Figure 1
This at-a-glance view sums up the status and health of an application running at multiple sites. It shows the application’s supporting components, processes and data.
Relying on autopilot
Monitoring and control are critical elements of a
dual system, but no product previously existed
that met the requirements of this type of environment.
So the Teradata Professional Services team created Dual
System Monitor and Control—the foundational architec-
ture for Teradata Multi-System Manager.
In a dual-system environment, Dual System Monitor
and Control can be compared to the instrument panel
in an aircraft’s cockpit—both monitor and manage the
system, both display multitudes of information, and when
problems occur, both activate autopilot.
The solution allows customers to monitor the status of
the dual-system environment, including load jobs, system
alerts, and data and application states. It provides con-
trol over the software, processes and servers that com-
prise the dual-system environment, and sets limits on the
users and applications that route between the systems.
Various levels of detailed information enable users to
see that their applications are operational and per-
forming as expected. A customer’s load architecture is
analyzed to determine how and where to inject instru-
mentation points. Data loads are then instrumented to
automatically broadcast their progress. An alert is sent to
operations when the data latency between the two sys-
tems is above tolerance, and database administrators can
be notified when data consistency issues are identified.
The system’s critical threshold levels are based on
service level agreements for application availability, data
latency and load and response times. When these thresh-
olds are crossed, appropriate alerts are generated and
status changes are visually displayed.
These automated features make it possible for custom-
ers to easily handle a complex dual-system data ware-
house that must be duplicated for reliability and consis-
tency while at the same time be query-accessible.
So, like pilots who rely on their instrument panel, users
can feel assured that the Teradata Multi-System Manager
will help control and enhance the performance of their
dual-system environment.
— Stan Mlynarczyk, director of the Enterprise Architecture
Center of Excellence, Teradata Professional Services
— Mark Mitchell, principal consultant, Teradata Professional
Services
PAGE 2 | Teradata Magazine | September 2008 | ©2008 Teradata Corporation | AR-5721
events within the environment—
everything from a summary view
of the components to a detailed
drill-down of which processes are
running or have been completed on
each system. (See figure 1, page 24.) In
addition, the summary view provides
feedback on the health and opera-
tional status of all components.
> Monitoring of servers, processes and
applications. Beyond a unified view,
intelligent monitoring of numerous
events within the environment is pro-
vided, including detection of system
operational status and the per-system
completion status of processes such as
load jobs.
> Simple point-and-click controls.
Features include a graphical user
interface portal with easy-to-use
controls to manage query routing
rules, engage or disengage a system
for planned maintenance, or bring
a system back online and up to date
after an unplanned outage.
> User routing based on application
readiness state. Sophisticated controls
manage which applications and users
can access which
system based on its
particular data cur-
rency and process
completion. This
capability ensures
that a system is
available and has
current data before
allowing applica-
tion and user access.
(See figure 2.)
> Monitoring
thresholds and dis-
crepancy report-
ing. Managing
multiple loosely
coupled systems
requires a level
of control as to
how current the data is between
the systems. Depending on how the
systems are used and which users
are accessing them, some amount of
data-drift can be tolerated. Anything
beyond this acceptable amount will
require the synchronization lag to be
tightened. Alerts will indicate when
the thresholds are crossed. The system
can also be programmed to take pre-
defined action when this occurs.
> Graceful failover and failback during
planned and unplanned outages.
When the goal is continuous access
for users, one of the most valuable
features in managing a dual-system
environment is the orchestration of
events to handle system outages. This
requires shifting workloads and users
between systems during planned and
unplanned outages. These different
scenarios have varying requirements
to handle the multiple permutations.
Flying highTo accomplish these tasks, Teradata
Multi-System Manager works with other
dual-system products and processes such
as Teradata Query Director and dual load-
ing of data. It controls the Teradata Query
Director profiles and makes modifications
on the fly to accommodate system status
changes. For example, if System A encoun-
ters an unplanned outage, the Query
Director profile is changed, which, in turn,
will engage a new set of routing rules. The
new rules might, for instance, limit routing
to only users with strict SLAs.
During the dual-loading process, the
system monitors the start/stop/completion
status of load jobs. It keeps track of which
jobs have completed and which have not,
and it runs synchronization checks on the
tables to ensure that all of the data was
loaded properly and that the data between
systems is in sync.
Teradata Multi-System Manager can also
be used in a single Teradata production
environment to monitor workflows among
the many application and load processes.
This will benefit Teradata customers who
plan to move from a single production
system to a dual-system environment in
the future.
With dual systems becoming main-
stream, it is important to have a solid
product that simplifies monitoring, admin-
istration and control of the environment.
Teradata Multi-System Manager provides
these capabilities with powerful features
that are efficient, dependable and simple
to use. T
Stan Mlynarczyk is director of the
Enterprise Architecture Center of Excellence
in Teradata Professional Services.
Rick Stellwagen is the engineering architect
for Teradata multi-system solutions.
Imad Birouty is program marketing man-
ager for the high-availability solutions and
data mart consolidation program at Teradata.
TOnlineFor more information,
visit Teradata.com/
DualActiveSolutions.
Summary view of all applications across two sites
Figure 2
The status and health of all Teradata ecosystems are monitored, and a condensed view is supplied of multiple applications and their conditions at each site.
PAGE 3 | Teradata Magazine | September 2008 | ©2008 Teradata Corporation | AR-5721