Responding to WTO buffer shortages
IEA405E WTO BUFFER SHORTAGE - 80% FULL
The
system also issues a DISPLAY CONSOLES,BACKLOG (D C,B) command to provide
information helpful in determining the cause of the buffer shortage.IEA404A SEVERE WTO BUFFER SHORTAGE - 100% FULL
IEA652A WTO STORAGE EXHAUSTED - WTOS WILL BE DISCARDED
At
this point, any new WTOs will be thrown away.- A console is not ready and WTO messages are filling the console
message buffers because:
- An intervention required condition exists.
- The console has been powered off.
- Some part of the path to the device is not working; for example, an I/O interface is disabled.
- One or more consoles may have their displays held.
- A console is not in roll mode, and messages are filling the console message buffers.
- A console is in roll or wrap mode but the update time is too long, and messages are filling the console message buffers.
- A buffer limit specified at IPL is too low to handle the message traffic in the system. (Either the value on the MLIM parameter in the CONSOLxx member is too low, or the system default for RLIM is too low.)
- A program is issuing messages at too rapid a rate and might be in a loop. When a job uses a high percentage of the WTO buffers, the system issues message CNZ3011I which identifies the jobname and the address space.
To determine the extent of the problem and the responsible console or consoles, examine the output from the DISPLAY CONSOLES,BACKLOG (D C,B) command. When messages are backed up for a console, it might be necessary to delete the queue of messages for the console using a CONTROL Q command. You might need to issue CONTROL Q several times to clear the console completely.
When there are too many messages from one job/address space, consider cancelling the job or jobs specified in message CNZ3011I. If cancelling a job would cause a serious impact, look at the messages the job is issuing. If the job seems to be in a loop, then activate an MPF member to suppress or delete the repeating message. Another option is to temporarily remove the message's routing code from all the consoles.
When a high number of buffers is in use for messages from another system in the sysplex, you can route a D C,B command to the other system to determine if a job on the other system is generating too many messages. You can protect your system from a runaway job on another system in the sysplex by using the V CN,DMSCOPE= command.
MSG: CURR=1356 LIM=1500 RPLY:CURR=1 LIM=10 SYS=1 PFK=NONE
CNZ4100I 17.08.05 CONSOLE DISPLAY FRAME 1 F E SYS=SY1
CONSOLES MATCHING COMMAND: D C,BACKLOG
MSG:CURR=1356 LIM=1500 RPLY:CURR=1 LIM=10 SYS=SY1 PFK=NONE
DAVE TYPE=MCS STATUS=ACT-SY1
DEFINED=(SY1)
MATCHED=(N/A)
ATTRIBUTES ON SY1
AUTH=(MASTER) CMDSYS=* NBUF=1217 SUPSBY=Y
DEV=03E0 LOGON=OPTIONAL USERID=N/A TIMEOUT=10
MFORM=(S) AREA=(Z,A) PFKTAB=01
USE=FC DEL=RD RTME=1/4 RNUM=25 SEG=19 CON=N
LEVEL=(ALL)
MONITOR=(NONE) INTIDS=N UNKNIDS=N
ROUT=(ALL)
MSCOPE=(*ALL)
ADDRESS SPACE WTO BUFFER USAGE
ASID - 0019 JOBNAME = FLOODNUM NBUF = 520
MESSAGES COMING FROM OTHER SYSTEMS - WTO BUFFER USAGE
SYSTEM = 2 NBUF= 4
If the buffer limit is not adequate, issue the CONTROL M,MLIM= command to increase the WTO buffer limit for the duration of the IPL. Your system programmer might code the MLIM parameter on the INIT statement in the CONSOLxx member to raise the WTO buffer limit for the next IPL.
IEA406I WTO BUFFER SHORTAGE RELIEVED
- All lines of an out-of-line multi-line status display that have not been presented occupy message buffers. Therefore, you should erase these displays when they are no longer needed.
- The current buffer count can be larger than the specified limit. Even though the buffer count is greater than or equal to the limit, the system always gives a privileged task a buffer unless the storage available for buffers is exhausted.
- The system does not use the MLIM and RLIM parameter values specified in the CONSOLxx parmlib member until either the hardcopy medium (SYSLOG or OPERLOG) becomes active or NIP processing is complete. After NIP processing, multiple consoles become active and buffer space becomes important.