Re: Informix crashing UNIX on HP

Jeff Kalchik wrote: > On Thu, 02 Oct 1997 16:19:24 +0200, "Mark D. Stock" > <mdstock@informix.com> wrote: > >Make sure you don't allocate more than ONE VIRT segment on an HP box. > >This is normally just a performance issue, but could be your problem? > > Wait a minute..... Why should I force Informix to use only 1 VIRT > segment? I assume you are referring to shared memory. What I assume Mark is referring to is the unfortunate behavior of HP/UX (at least up to v 10.10 or so - could be fixed in 10.20, but I don't know for sure) to not handle more than 3 shared memory segments per process with any grace. It seems once you go beyond three, it pages all the shared memory segments out to disk, so that any access of shmem results in disk i/o. Thus the limit is not specifically aimed at virtual segments; but since you will have one resident segment and, if you are using shmem connections for the client/server communication, one message segment, you are left with only one segment for virtual memory. If you eliminate the message segment by only configuring tcp/ip connections, you could have 2 virtual segments without running into trouble. Again, this is specific to HP/UX. And you are theoretically not limited to the amount of virtual memory, as you could make the one segment as large as your kernel allows - it's the number of segments that is significant. As to the original point, I have to concur with Mark that I have never seen this cause a crash in HP/UX, only performance problems. -- Dave "That's just my opinion - I could be wrong." - Dennis Miller