Shared Memory Connections

The service name for shm connections is often labelled dummy, this is fine if you are on single instance. But if you are running multiple instances then the name must be unique across all instances.


onstat is 100% 
dbaccess says the instance is not running 
onparams runs against the last engine started 
onspaces runs against a random engine 

Put it into shared memory servicename in /etc/services anyway, it cannot hurt, and will remind you not to use the same name twice

Author: June Hunt

Non-unique servicenames or servernames. DSA creates files in /INFORMIXTMP for your shmem and tcp connections (I don't know about others), which are named by servicename (for tcp) and servername (for shmem). If these are not unique on the machine, one will overwrite the other.

TCP Connections

You must not use the same service name for the shared memory entry in sqlhosts as you do for any other entry for the same server. If you do the server will begin polling that service which will spin the CPUs and generate thousands of unneeded system calls per second. You are correct that the service name used for shared memory connections does not need to be in /etc/services it is a dummy and can be anything, but must not be the same as that used by another protocol on the same service.

Personal Tools