A fix is available
APAR status
Closed as program error.
Error description
A large number of TCP connections are terminated simultaneously resulting in large number of finwait2 timers scheduled in the same time slot. When the timer expires, the termination processing of each connection results in an expansion of the dynamic savearea (DUSA). Each DUSA expansion results in the use of an additional 36k ( x'9000' ) area of storage. The spike in ECSA, subpool 241 key 6, storage can cause ECSA to be depleted.
Local fix
If the TCPIP stack leaves the sysplex, once ECSA storage use by TCPIP is no longer an issue, the VARY command VARY TCPIP,,SYSPLEX,JOINGROUP can be issued to allow the TCPIP stack to rejoin the sysplex. TCPIP's ECSA storage use can be monitored with the command DISPLAY TCPIP,,STOR ADDITIONAL SYMPTOMS: - If SYSPLEXMONITOR is enabled, the storage shortage could cause the stack to leave the sysplex. This would be accompanied by EZD1973E MULTIPLE TCPIP NONRECOVERABLE ERRORS ARE ADVERSELY AFFECTING SYSPLEX PROCESSING and EZZ9676E SYSPLEX PROBLEM DETECTION CLEANUP HAS SUCCEEDED FOR TCPIP messages. . KEYWORDS: AB4C5 4C5 2500 RC2500 SP241 K6 241 6 DUCB DUSA 9000 FINWAIT2
Problem summary
**************************************************************** * USERS AFFECTED: * * All users of the IBM Communication Server * * for z/OS Version 2 Release 1 IP: * **************************************************************** * PROBLEM DESCRIPTION: * * ABEND4C5 RC74FF2500 ECSA storage * * shortage during simultaneous * * termination of TCP connections. * **************************************************************** * RECOMMENDATION: * * Apply fix. * **************************************************************** The problem can be summarized as follows: 1. A server was terminated resulting in a FIN request sent to each connection partner client. 2. The client ACKed the FIN, but did not return a FIN. 3. The TCP server host started a FINWAIT2 timer. 4. All FINWAIT2 timers expired simultaneously and proceeded with connection cleanup. 5. Each process executing connection termination obtained DUCB/DUSA control blocks from ECSA storage. The amount storage obtained caused a temporary storage spike in ECSA usage and exceeded available ECSA.
Problem conclusion
TCPIP has been modified to not process all FINWAIT2 timer expirations simultaneously, and therefore avoid a storage spike.
Temporary fix
Comments
APAR Information
APAR number
PM97943
Reported component name
TCP/IP V3 MVS
Reported component ID
5655HAL00
Reported release
210
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2013-09-26
Closed date
2014-01-16
Last modified date
2014-04-02
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UI14307
Modules/Macros
EZBTCRD
Fix information
Fixed component name
TCP/IP V3 MVS
Fixed component ID
5655HAL00
Applicable component levels
R210 PSY UI14307
UP14/03/13 P F403
Fix is available
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Document Information
Modified date:
02 April 2014