z/VM: CP Commands and Utilities Reference - z/VM - IBM

v A virtual machine must load the monitor saved segment and connect to
*MONITOR for sample data
v A MONITOR START or MONITOR SAMPLE START command must be
issued.
If the START command is issued when no virtual machine is connected with an
active path to *MONITOR for sample data, sample recording is held pending
until there is a connection with an active path.
2. The intervals for sample data collection start at the time the sample start
command is issued. Monitor does not generate sample records unless there is
at least one eligible monitor user for sample data. The following are two
examples for the condition mentioned above:
v Example 1
a. MONITOR SAMPLE START is issued at 10:00 A.M. with 10-minute
intervals.
b. A user connects to *MONITOR at 10:05 A.M. to collect sample data. The
sample configuration records are generated at the connect time (10:05
A.M.), and the first data records are generated at 10:10 A.M.
v Example 2
a. A user connects to *MONITOR at 10:00 A.M. to collect sample data.
b. MONITOR SAMPLE START is issued at 10:05 A.M. with 10-minute
intervals. The first sample data records are generated immediately after
the sample configuration records are generated (at 10:05 A.M.). The next
sample interval is at 10:15 A.M.
3. It is possible for a user who connects to *MONITOR for sample data collection
to receive two record notification messages—one for sample configuration
followed by one for the sample data records. See 639 above.
4. The sample configuration message might be delayed for a user who connects to
*MONITOR to collect sample data, and in turn the sample data notifications are
also delayed for the user.
v If another user has already connected to *MONITOR to collect sample data
and has not replied to the sample configuration message, the monitor
regenerates the configuration records after the configuration area is free and
sends a sample configuration message to the user who just connected to
*MONITOR.
Note: If the MONITOR SAMPLE START command is issued before any user
is connected to *MONITOR, the first user connected to *MONITOR
holds the configuration area. When that user issues an IUCV REPLY
or the configuration time limit expires, the other users who are
connected receive data notification for a new set of configuration
records.
v If a user’s path to *MONITOR is quiesced (or at its IUCV message limit)
when the sample configuration notification is sent, the user receives
notification for a refreshed set of configuration records when he or she
resumes his path (or responds to one or more previous messages).
5. Both event and sample monitoring can be active at the same time. The
MONITOR SAMPLE START command only starts sample monitoring. To start
both event and sample monitoring, use the MONITOR START command
described in “MONITOR START/STOP” on page 643. Similarly, MONITOR
SAMPLE STOP stops only sample monitoring while MONITOR STOP stops
both event and sample monitoring.
Specific Usage Notes for I/O:
MONITOR SAMPLE
Chapter 2. CP Commands 639