PFS UDS MAXSOCKETS for AF_UNIX

The AF_UNIX socket limit is controlled by z/OS Unix System Services. Your request has been assigned to z/OS Communications Server. Reviewing your request we are concerned with the potential implications your workload has in regard to syslogd. The syslogd server has a single AF_UNIX socket that it receives messages on. The application address spaces implementing syslog() requests will all connect to the syslogd socket. The written messages are buffers in memory on the syslogd socket end point until they have been read. The AF_UNIX socket has a limited buffer space. When this buffer space becomes full the syslog() function will receive a -1 EWOULDBLOCK return code on its write request and internally it will iterate the write for up to 7 minutes before returning to the application. If the workload that is causing the AF_UNIX socket limit to be reached consists mostly of syslog() related sockets your environment may be exposed to prolonged application delays waiting on syslog() calls to return.

Is the application workload hitting the 10,000 socket limit due to syslog() opened AF_UNIX sockets or is the workload also using AF_UNIX sockets to communicate between processes unrelated to syslogd? If the socket limit is caused by syslog() sockets is there any expectation that the owning application instances will write numerous messages in parallel such that syslogd might be overwhelmed to the point where its socket buffer becomes full? Increasing the limit of AF_UNIX sockets to accommodate more syslog() sockets is going to increase the likelihood of syslogd not being able to read messages as fast as they are sent, and thus introduce delays in the applications issuing syslog() requests.

Any details you can provide on the expected messaging rate would be helpful.