IDS Forum

Re: Can I bring informix up/down from another ....

Posted By: Fernando Nunes
Date: Friday, 27 October 2017, at 9:59 a.m.

In Response To: RE: Can I bring informix up/down from another .... (Mueller, Daniel D.)

Hmmmm.... traditionally AIX devides the memory in "cache" and "program"
memory. There were AIX versions (maybe late 5/ early 6) where the defaults
tended to consider the machines were mainly file servers (!).
So, heavy filesystem usage could "steal" program memory that could end up
being paged out...

But current versions AFAIK have reasonable defaults... It's a bit confusing
issue... Involving an AIX specialist would be my advice....

Regards and good luck.

On Fri, Oct 27, 2017 at 1:23 PM, Mueller, Daniel D. <DDMueller@west.com>
wrote:

> Fernando,
>
> Our "memory issue" in Not Informix related. It comes from the OS. I have a
> suspicion that opening a very large file loads the entire file into memory
> and
> that is causing the issues. Unfortunately, we are not close to our
> sysadmins
> and we have not been able to prove/disprove that out. PMRs have been opened
> and closed w/o much ado.
>
> We continue to try to get this one figured out but I have not seen Informix
> grow past SHMTOTAL (not set to 0). Thank you so much for the followup
> though.
> I do appreciate all the help I can get.
>
> Dan
>
> -----Original Message-----
> From: ids-bounces@iiug.org [mailto:ids-bounces@iiug.org] On Behalf Of
> Fernando
> Nunes
> Sent: Friday, October 27, 2017 5:33 AM
> To: ids@iiug.org
> Subject: Re: Can I bring informix up/down from another .... [40108]
>
> I didn't want to elaborate too much on this. I tried to answer the question
> only... But "memory issues" are either a bug (memory leak) which must be
> fixed, so a PMR must be opened, or bad engine / OS configuration (don't
> take
> this as criticism).
> Either case needs investigation.
>
> Informix should not "eat" that much memory that would prevent a login on
> the
> machine. And it will only happen if SHMTOTAL is set to "0". I usually
> recommend against this setting, precisely because a runaway engine can
> "eat"
> all the system memory and affect other instances on the same system or the
> system itself. Naturally if a customer only has one instance on the machine
> this is not as critical.
>
> Now... The big problem in setting it to something differently than "0" is
> that
> the parameter is not dynamic! I find it hard to understand why we can't
> (yet)
> change it dynamically at least to increase it. I could imagine issues on
> decreasing it (if we try to lower it beyond the current instance usage. But
> you already know me... I always think some code changes are easy...
> probably
> because I don't mess with the code myself, and because I don't have a tight
> agenda of features and important customers pressuring with features I
> consider
> less important :) In other words, speaking is easy, doing it might me
> slightly
> harder :)
>
> Regarding RESIDENT set to -1... specially for AIX... again I think it's
> kind
> of a myth. I understand why we started to recommend this, and I know we had
> issues with KAIO (
> http://www-01.ibm.com/support/docview.wss?uid=swg1IC76872) but again...
> It's mainly a misconfiguration and some "dumb"(?) AIX defaults (pinnable
> memory). Naturally, considering the seriousness of the possible effects,
> -1 is
> the safe and simple recommendation.
>
> Regards.
>
> On Fri, Oct 27, 2017 at 8:55 AM, Andreas Legner1 <
> Andreas.Legner1@de.ibm.com
> > wrote:
>
> > Also: RESIDENT -1 ?
> >
> > Could be contributing to 'memory issues', and shouldn't be required on
> AIX.
> >
> >
> > ************************************************************
> > *******************
> > Forum Note: Use "Reply" to post a response in the discussion forum.
> >
> >
>
> --
> Fernando Nunes
> Portugal
>
> http://informix-technology.blogspot.com
> My email works... but I don't check it frequently...
>
>
> ************************************************************
> *******************
> Forum Note: Use "Reply" to post a response in the discussion forum.
>
>
> ************************************************************
> *******************
> Forum Note: Use "Reply" to post a response in the discussion forum.
>
>

--
Fernando Nunes
Portugal

http://informix-technology.blogspot.com
My email works... but I don't check it frequently...

Messages In This Thread

• Can I bring informix up/down from another computer
  DAN MUELLER -- Thursday, 26 October 2017, at 12:50 p.m.
  • Re: Can I bring informix up/down from another comp
    Fernando Nunes -- Thursday, 26 October 2017, at 1:31 p.m.
    • Re: Can I bring informix up/down from another ....
      Andreas Legner1 -- Friday, 27 October 2017, at 2:55 a.m.
      • Re: Can I bring informix up/down from another ....
        Fernando Nunes -- Friday, 27 October 2017, at 5:33 a.m.
        • RE: Can I bring informix up/down from another ....
          Mueller, Daniel D. -- Friday, 27 October 2017, at 7:23 a.m.
          • Re: Can I bring informix up/down from another ....
            Fernando Nunes -- Friday, 27 October 2017, at 9:59 a.m.
            • Re: Can I bring informix up/down from another ....
              MARK JALKIEWICZ -- Friday, 27 October 2017, at 10:25 a.m.

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