Use
the VTAM Buffer Pool Usage By Category attributes to monitor the usage
of the IO00 buffer pool based on contents.
The IO00 buffer pool manages the storage of all network input/output
messages sent from application programs and across channel connections.
All network traffic passes through this pool, regardless of its destination.
This buffer pool also contains channel programs used to service locally
attached devices.
Because a great deal of activity takes place in the IO00 buffer
pool, it is very sensitive to dynamic fluctuations in traffic rates.
Consequently, it is a prime candidate for tuning. Examining the contents
of this buffer pool can help a network capacity planner plan for more
common storage area (CSA), understand how applications are using the
pool, and understand the network traffic activity.
The values reported in this attribute table are obtained by processing
the contents of the buffers themselves, and the VTAM control blocks
are examined to determine which of the two categories each of the
buffers in the IO00 pool is to be associated with.
Buffer Pool Category The VTAM IO00 buffer pool usage category. Valid
responses are User Category or User Category 2. Use
the information below to determine the types of buffers in each user
category:
User Category: Each buffer in the IO00 buffer pool is examined
to determine if it falls into each of the following areas.
- Unallocated buffers
- Read channel program buffers
- Buffers with a Transmission Subsystem Control Block (TSCB)
- Miscellaneous category consisting of buffers that do not meet
any of the criteria of the previously listed categories
The relative percentage of buffers for each of these categories
is calculated and displayed.
User Category 2: Each buffer in the IO00 Buffer Pool which
contains a TSCB is examined to determine if it falls into each of
the following areas.
- SSCP traffic
- Virtual route pacing response traffic
- APPL(PLU) to same subarea resource traffic
- APPL(PLU) to a different subarea resource traffic
- APPL(SLU) to a different subarea resource traffic
- Local SNA resource to a different subarea APPL traffic
- Local non-SNA to a different subarea
- Intermediate routing node traffic
The relative percentage of buffers for each of these categories
is calculated and displayed.
Buffer Pool Name The
name of the VTAM buffer pool. This value is always IO00 in this
attribute group.
Collection Time The
time and date of the data sampling. This time is displayed in
the following format:
mm/dd/yy hh:mm:ss (Tivoli Enterprise Portal) or yy/mm/dd hh:mm:ss (3270)
Where:
- mm = Month
- dd = Day of the month
- yy = Year
- hh = Hour
- mm = Minute
- ss = Seconds
The stored format is a string no longer than 16 characters in the
format CYYMMDDHHMMSSmmm (as in 1020315064501000 for
03/15/02 06:45:01) where:
- C = Century (0 for 20th, 1 for 21st)
- Y = Year
- M = Month
- D = Day
- H = Hour
- M = Minute
- S = Second
- m = Millisecond
Description The
description of the buffer based on the contents of the buffer. The
format is an alphanumeric string no longer than 40 characters. This
field can have the following values:
- APPL (PLU) to Different Subarea Resource: I/O buffers being
used for traffic flowing between a primary logical unit (PLU) application
and a secondary logical unit (SLU) source in another subarea.
- APPL (PLU) to Same Subarea Resource: I/O buffers being
used for traffic flowing between a primary logical unit (PLU) application
and a secondary logical unit (SLU) resource (both in this host).
- APPL (SLU) to Different Subarea Resource: I/O buffers being
used for traffic flowing between a secondary logical unit (SLU) application
on this host and a primary logical unit (PLU) application in another
subarea.
- Intermediate Routing Node Traffic: I/O buffers being used
for traffic flowing between two resources, neither of which is in
this subarea
- Local Non-SNA to Different Subarea APPL: I/O buffers being
used for traffic flowing between a local non-SNA terminal and an application
in another subarea.
- Local SNA to Different Subarea APPL: I/O buffers being
used for traffic flowing between a local SNA terminal and an application
in another subarea.
- Misc: I/O buffers that could not be categorized. This number
includes path information units (PIUs) that could not be classified
because of state changes in VTAM, as well as channel programs (other
than read).
- Read Channel Programs: I/O buffers being used to hold read
channel programs. VTAM uses read channel programs to transfer data
from the NCP or local cluster control units and perform a read channel
operation. A read channel program consists of a string of channel
command words (CCWs), each allocated at the beginning of an I/O buffer.
VTAM transfers the data in blocks, each the size of an I/O Buffer.
- SSCP Traffic: I/O buffers being used for traffic to and
from the System Services Control Point (SSCP). The SSCP provides resource
management and control for the network. This field does not include
the virtual route pacing response traffic.
- TSCBs: This is the total number of Transmission Subsystem
Control Blocks (TSCBs) in the IO00 buffer pool. Each TSCB contains
a Path Information Unit (PIU).
- Unallocated Buffers: Buffers currently unallocated and
available.
- Virtual Route Pacing Response Traffic: I/O buffers being
used for virtual route pacing responses (VRPRSs). A VRPRS flows in
response to a request to send another full window of path information
units (PIUs). If this value is high, the maximum window size might
be too small. Or, there might be a large number of virtual routes
defined and active.
Origin Node The
unique identifier for the VTAM job being displayed. The format
is an alphanumeric string no longer than 32 characters.
Percent Percentage
of the described buffer (which is based on its content) relative to
the other buffers within its user category. The format is an
integer.
System ID The
SMF system ID. The format is an alphanumeric string no longer
than 4 characters.