Explanation
VTAM® detected
that the session indicated is using 10 percent or greater of the bpBUF
buffer pool.
nodename1 and nodename2 are
the session partners for the session using the largest percentage
of the pool. VTAM issues nodename1 and nodename2 as
network-qualified names in the form netid.name.
If VTAM does not know a node
name, the node ID is presented in the form subarea/element,
where subarea is the subarea and element is
the element portion of the network address.
bpBUF,
the name of the buffer pool, will always be IO.
percentage is
the percentage of this buffer pool used by this session.
If
the session between nodename1 and nodename2 is
not using a large percentage of the buffer pool, the size of the buffer
pool was probably underestimated.
If the session between
nodename1 and
nodename2 is
using a large percentage of the buffer pool, one of the following
conditions probably exists:
- Either nodename1 or nodename2 is
malfunctioning. This could be a hardware, microcode, or application
program error that causes VTAM to
be flooded with data.
- Neither nodename1 nor nodename2 is
malfunctioning, but a large amount of data is being transmitted on
this session with no pacing in effect.
System action
Message IST154I, IST1098I, or IST1099I is displayed
with this message.
- If message IST154I is displayed, the buffer pool is not expanded
at this time. When more storage becomes available, VTAM may try again to expand the buffer pool. VTAM may be adversely affected
by this failure to obtain more buffers.
- If message IST1098I or IST1099I is displayed, processing continues.
- If the session is an SSCP-LU session, then the LU is deactivated,
and message IST1098I is displayed.
- If the session is an LU-LU session (including CP-CP) then the
session is terminated, and message IST1099I is displayed.
Once VTAM has determined
that a session is using greater than 10 percent of the buffer pool,
a determination is made whether to automatically terminate the session.
If the percentage is greater than or equal to the HOTIOTRM start
option value, VTAM initiates
termination of all the sessions between
nodename1 and
nodename2. VTAM issues message IST1099I when
sessions are automatically terminated.
Operator response
- If it appears that the problem is caused by a malfunctioning device
LU, try to deactivate the device using the VARY INACT command. In
extreme cases, you may have to physically disconnect or power off
the device.
- If it appears that the problem is caused by a VTAM application program, take a dump of that
program and terminate it. Save the system log for problem determination.
- If VTAM continues to issue
this message, enter the DISPLAY BFRUSE command. Save the system log
and request a dump for problem determination.
System programmer response
- Ensure that session pacing is in effect for the session using
the largest percentage of the buffer pool. The BIND request unit contains
the values used for each session. See the z/OS Communications Server: SNA Network Implementation
Guide for more information about session pacing.
- If message IST154I is displayed before this message, and the session
between nodename1 and nodename2 is
not using a large percentage of the buffer pool, the size of the buffer
pool was probably underestimated.
- If message IST154I was issued, use the explanation of code in
that message to determine which buffer pool you need to modify.
- You might want to redefine your buffer pool or CSA start options.
If the start option cannot be modified using the MODIFY VTAMOPTS command,
you must modify the VTAM start
options file (ATCSTRxx) and restart VTAM to use the start option.
- If you want VTAM to automatically
terminate these sessions, specify the HOTIOTRM start option with a
value that is less than or equal to percentage.
This start option can be modified using the MODIFY VTAMOPTS command.
- For additional information, see:
Routing code
Descriptor code