SirMon
(A print-quality
reproduction of this brochure is available in
pdf format.)
SirMon is a system monitor and operations control utility for
Model 204. It provides a centralized means for information
collection, problem resolution, and systems tuning within the
Model 204 environment. The flexible format of SirMon's expanded
sets of system, subsystem, file, and user statistics are easily
customized. The user interface links to a command set that supports
timely and informed decision support and system control.
The clear organization of real-time information provided by SirMon
eliminates the need to cross-reference data from multiple sources
to determine the cause of problem situations. SirMon saves both
time and human resources needed to perform System Managers and
DBA functions. This increases the likelihood that problems will
be resolved quickly.
Automated Monitoring and Problem Reporting
SirMon provides three levels of automated monitoring.
First, SirMon provides an auto-refresh mode for displays, that
enables precisely timed presentation of performance statistics
and permits a terminal to be set up as a "
hands-off"
system monitor.
Second, SirMon enables users to set thresholds for any statistic
on the System Overview screen. The System Overview screen provides
information about all key areas of system performance including
resource consumption and response-time. When any statistic has
exceeded its user-specified threshold, it is highlighted on the
System Overview screen allowing System Managers to quickly identify
any potential problems from a single screen.
The third level of automated problem reporting is performed by
the SirMon background task, which runs as an IODEV3 user, monitoring
system status and sending warnings when problems are detected.
The background task uses the same user-specified thresholds as
the System Overview screen. In addition, users can specify the
monitoring interval, the number of intervals across which a problem
must exist before SirMon sends warnings, a message-latency period
that prevents excessive warnings, and a list of users (including
the operator and the journal) to receive messages. The background
monitor, combined with Sirius' expanded set of system measures-including
a number of response-time indicators-provides timely and highly-detailed
performance checking with very little user setup or manual intervention.
Dynamic User Restart
In those extreme cases where a single user is "
looping"
,
and preventing other activity from occurring in the Model 204
address space, a restart option allows the operator to restart
only the looping user from outside the on-line without affecting
other "
healthy"
users. This provides a number of information-gathering
options, and increases the likelihood that the on-line will continue
to run or, if it must be brought down, that a recovery step will
not be required.
System Managers
With SirMon, System Managers receive a clear picture of problems
occurring within an on-line and of the results of the actions
they may take to correct the problems. SirMon removes the guesswork
from problem resolution. By using SirMon, the System Manager increases
his or her knowledge of the local database environment and of
the kinds of activity that indicate performance or operational
problems.
File Managers
File managers and application designers will also find their workload
eased by SirMon's ability to collect and present the precise information
needed to develop and maintain database applications. Any resource
which is capable of being adjusted, such as UTABLE settings, server
size, or CPU, can be displayed along with the user, file, or procedure
using the resource. File Table usage can be viewed in a single
scrollable set of information for all files open in the on-line.
In addition to addressing these important day-to-day operational
problems, SirMon provides information that is essential to fine-tune
performance and evaluate the overall efficiency of an on-line
configuration. Performance projects may target the system as a
whole, or focus on specific applications, procedures, or internal
resources such as servers, index structures, or subtask offload.
To establish a threshold for any statistic
on the System Overview screen, one simply enters the desired statistics
alarm level on the Thresholds Screen.
To control the timing of the monitor interval
and warning information, one simply enters the desired parameter
values in the Background Monitor Screen
One way that SirMon users are notified
that thresholds have been exceeded is by highlighting (bold or
red) of the relevant statistics on the System Overview Screen
Another way SirMon users can be warned
that limits have been exceeded is to have SirMon send a system
message to one or more users on the system.
SirMon provides the ability for users
to design screens that display the specific statistics needed
for their environment. This is done by choosing the desired statistics
from the User Selected Monitor Screen.
SirMon contains an on-line dictionary
of Model 204 Statistics. The descriptions of these statistics
help the user to identify the most appropriate statistic for the
task.
This is an example of a screen that would
be generated by the statistics selected in the screen shown above.
The information is presented in a clear and concise fashion. It
may be scrolled, sorted, and examined at various levels of detail.
The information is displayed in real-time.
Examples of the operations concerns addressed by SirMon include
the following:
- You want to free a file. How do you identify who's holding
it? In SirMon you can monitor all users and then limit the display
to only those holding open a specified file. The Subsystem monitor
screens are used in exactly the same way to identify APSYs holding
open a particular file.
- The checkpoint dataset regularly fills up. By monitoring users
and limiting the display with a CHKP command, only those users
preventing the checkpoint from taking place are displayed, along
with any statistics you choose, (in this case, the procedure name
and subsystem might be shown). This simple facility of monitoring
on one entity and then restricting the view by another allows
great flexibility in targeting specific enqueueing or performance
situations.
- A long-running request prevents users from sharing the system.
Usually there is little choice but to physically locate the person,
find out what they're executing and make a decision regarding
the user's session. With SirMon, the user, the level of resource
consumption, the procedure, APSY, and file can all be seen instantly
on a single screen. The user may still be bumped or the manager
may reduce the user's priority (even to O) while the problem is
investigated.
- You want to compare transaction rates against published benchmarks,
or against those claimed by another application. SirMon allows
you to view changes in any resource per screen I/0, per user-specified
time interval, or per event that you define by 10 locally-defined
and locally incremented event counters built into SirMon. SirMon's
"
hands-off"
mode of operation allows sub-second precision
in determining your transaction rates.
- A case has been made for changing the current mix of servers.
A single screen in SirMon will show you the procedure each user
is running, the size server they require and the size they got.
The same process is used to show UTABLE settings in relations
to procedures and users.
- Monitoring of file table usage takes too much time. SirMon
reduces this task to mere seconds by displaying all file table
usage information in all open files in a single set of data which
can be scrolled and sorted.
SirMon answers performance and data availability questions
that cannot be answered by other means. For example:
- What is your peak sustained transaction rate?
- How often do you have server swaps for things other than terminal
I/O?
- Do you have critical file resource bottlenecks on any database
files?
- What is the cause of these bottlenecks?
- Is the checkpoint or journal dataset ever a bottleneck on
your system?
- How widely does CCATEMP utilization vary in the course of
a day?
- How about record locking table utilization?
- Is your on-line getting all the CPU time it wants or needs
at peak hours?
- How often do you do VTAM buffer waits?
- Does your on-line's virtual storage utilization vary over
the course of the day?
- What is your peak sustained server I/O rate? What is your
peak sustained database I/O rate? Do they occur at the same time?
- How much of your database l/O at peak times is CCATEMP I/O?
- What is your peak IFAM call rate?
- What is the typical number of users "
waiting for server"
at peak times and what size server do they require?
Are any of these potential bottlenecks keeping you and your users
from exploiting the full power of your database?
Summary
SirMon is the only tool designed for Model 204 operations
management. SirMon is fully compatible with all CCA-supported
versions of Model 204, and is kept up to date by Sirius Software.
SirMon's set of operations tools and performance tuning features
is the professional choice for operations management, performance
monitoring, and problem solving in Model 204.
