Re: Informix and Oracle or Sybase on the same server

In some cases, to have Informix run on the same host as another server, you will have to change the default instance number (0). This problem occurs for example under AiX, because the shared memory segment address is fixed and must not be changed. In some cases, this causes conflicts with global shared memory segments allocated by other servers. The problem is solved by changing the instance number from 0 (the default) to 10 for example, or unother higher value, so that the Informix server does not conflict anymore with another one. In fact, the instance specific memory block is allocated at an address which depends on the base address of the shared segment, and on the instance number. I had this problem running concurrently Sybase 11 and Informix Online 7.22 on the same AiX 4.2.5 box (which fixes the shared memory segment address). I solved it by simply changing the instance number for Informix from 0 to 10. Failing to do so caused an error allocating the shared memory segment for the server (reported in the online.log trace file), followed by a Informix server panic (server does not start up). This problem occurs on AiX because it lacks of the system API's to know the current map of shared memory handles allocated. Sometimes, when the Informix server panics and shut downs ungracefully, the shard memory block is not released, and the host must be rebooted in order to drop the shared memory segment and its associated global handle. There should be a way under AiX to kill lost shared memory block descriptors, but any attempt to do so (using shm_control from root account) failed: the block is present and allocated, but AiX refuses to unlock and dispose it, or to reuse it when the server is restarted. -------------------==== Posted via Deja News ====----------------------- http://www.dejanews.com/ Search, Read, Post to Usenet