Are you using the shared memory interface to connect to the engine? If so
then the message buffers count against the limit of 10. So if you ran into
trouble after 2 segments were added, then I suspect that you might be
running with 6 message buffer segments. That would be 6 message buffer
segments, 1 buffer pool segment, 1 initial virtural segment, and 2 extension
segments.

Post the output of onstat -g seg so we can check to see if that is the case.

M.P.
<jpierrot@chubb.com> wrote in message
news:1108494664.6cafd5ec1dd1c5ae0967ee6580fa4425@t eranews...
>
>
>
> Can anyone help shedding some light on the following issue. Informix IBM
> tech is saying one thing while IBM AIX tech contradicts its counterpart.
> I have one IDS instance on AIX 5.2 and the Informix ver is 7.31.UD7 ,
> 32bit
> SHMVIRTSISE set to 1100000
> SHMADD set to 100000
> BUFFERS set to 200000
> SHMTOTAL set to 0
> Physical Memory of Box is 8GB
> The total instance size is about 2GB or 1.94GB (1944016)
> One day the instance try to add segments to support the workload. It added
> one successfully and about 1 hour later it hung and finally went down
> while trying to add another segment with the following MSG.
>
> shmat: [EMFILE][24]: out of shared memory segments, check system SHMSEG
> shmdt: errno = 22
> From talking to Informix I gathered the following info :
>
> AIX has OS limitations which are not tunable on most versions.
> (dynamically manage by OS)
> It allows 10 segments per process (SHMSEG 10) and the maximum size
> for a segment is 2 gigs. Consider checking with AIX tech support, to see
> if there are any
> OS patches which can help overcome this obstacle.
> Note : The keyword here is: a segment
> My segment was still under the two gigs limitation and also I tested and
> were only able to dynamically add 2 segments on a test box under the same
> configuration. I ended up with the same scenario. But after setting the
> environment variable :
> EXTSHM
> I was able to add one more to a number of 3 segments
> ***
> But IBM AIX tech support stated :
> 2 gigs is the architectural limit for a 32 bit O/S.
>
> Does that translate to a 2gigs limitation per process and your instance
> total memory size cannot grow beyond 2 gigs in a 32 bit platform
> If the above doesn't hold true, is there a workaround to this issue?
> Are there any shared memory parameters in AIX that can be tuned to
> address the problem
> Is 64bit the only solution. (I am not trying to go that route yet till
> next year IDS9.x migration, but our platform is 32/64bit)
>
> Your insights would be greatly appreciated. Thanks in advance.
>
> Josue'
>
>
> sending to informix-list