IDS Forum

RE: 11.5 UC7E crashes

Posted By: Marcus Haarmann
Date: Wednesday, 21 December 2011, at 3:06 a.m.

In Response To: 11.5 UC7E crashes (KLAUS GLAHN)

Hi,

looks like a shared memory problem. The max SHMEM addressable under
Debian (I assume 32bit)
is about 2.7 GB. If you run into problems below this mark, check your
shared memory parameters.
It also depends on the running kernel. If you are using a bigmem kernel,
there can be more shared
memory than in a standard kernel. Running the 32bit version in a 64bit
env with ia32 is also
possible and gives you about 3.4 GB of shared memory adressable because
the shared libs are loaded
in a higher segment there. This leaves more space for shared memory.

I assume you have done a transaction which requires lots of memory,
otherwise your memory
would not increase to 1.3 GB.
Maybe you get into the problem because the number of segments is too
high.

Try the following (depending on your machine configuration, should be
3GB min):
SHMVIRTSIZE 800000 # initial virtual shared memory segment
size
SHMADD 150000 # Size of new shared memory segments
(Kbytes)

that way the machine allocates 800MB initially and increases shared
memory in 150MB steps.
(your setup is 32K initial and 8K increase, which leads to a lot of
segments when 1.3GB is filled).

The reached memory limit address looks like the begin of the shared
libraries on a standard kernel.
You can also try to lower the SHMBASE parameter to get more free mem for
shared memory.
Lowest is 0x10000000, which we hav done on a 64bit system running ia32.
This should be tried first !
(look in /proc/<processid of first oninit/maps to see what is
allocatable)
You can see from the error messages that IDS tries to find mem below the
given SHMBASE. (0x43800000)

Check on a separate system how memory size can be allocated with a dummy
instance
(start system given the parameters above and allocate shared memory with
onmode -a 150000
until you get an error message).
Check onstat -g seg in your active instance. It is not forbidden to have
multiple SHM Segments but you should monitor them.

Warning: if you set too high shared memory initially, we once ran into a
problem with backup via shared memory (might be solved).
For us, 800000 is a working value.

Hope this helps,

Marcus

-----Original Message-----
From: KLAUS GLAHN [mailto:glahn@berlinale.de]
Sent: Tuesday, December 20, 2011 8:07 PM
To: ids@iiug.org
Subject: 11.5 UC7E crashes [25681]

Hi,

we have an Informix Server 11.5 UC7E running under Debian Linux. The
system ran fine in no-logging-mode for several years until we switch to
logging-mode to support a new application.

Since then we experience crashes - the database dies with the following
messages from the online.log:

18:09:34 Assert fehlgeschlagen: Bedingung nicht erfllt (Bad block
pointer 0x893fe2c in pool 0x28632028), In (mt_shm_free)
18:09:34 IBM Informix Dynamic Server Version 11.50.UC7E
18:09:34 Wer: Session(137915, hoffmann@tefix, 6734, 0x38e64e80)

Thread(141348, sqlexec, 3ede9f40, 1)

File: mtshpool.c Line: 4193
18:09:34 Aktion: Bitte informieren Sie die technische Untersttzung fr
IBM Informix.
18:09:34 stack trace for pid 8244 written to
/opt/informix/tmp/af.2c0cc14d
18:09:34 Siehe auch: /opt/informix/tmp/af.2c0cc14d
18:09:36 Bedingung nicht erfllt (Bad block pointer 0x893fe2c in pool
0x28632028), In (mt_shm_free)
18:09:36 stack trace for pid 8244 written to
/opt/informix/tmp/af.2c0cc14d
18:09:36 Assert fehlgeschlagen: No Exception Handler
18:09:36 IBM Informix Dynamic Server Version 11.50.UC7E
18:09:36 Wer: Session(137915, hoffmann@tefix, 6734, 0x38e64e80)

Thread(141348, sqlexec, 3ede9f40, 1)

File: mtex.c Line: 491
18:09:36 Ergebnisse: Exception Caught. Type: MT_EX_OS, Context: mem
18:09:36 Aktion: Bitte informieren Sie die technische Untersttzung fr
IBM Informix.
18:09:36 Siehe auch: /opt/informix/tmp/af.2c0cc14d
18:09:38 Starting crash time check of:
18:09:38 1. memory block headers
18:09:38 2. stacks
18:09:38 Found bad memory block; address:29acfc88
18:09:38 mtex.c, line 491, thread 141348, proc id 8244, No Exception
Handler.
18:09:39 Der Master-Dmon ist nicht mehr aktiv
18:09:39 PANIC: Attempting to bring system down

I am not an Informix expert, but responsible for the system. The
internet is not helping with these error messages.

I dont know if this is important or has anything to do with the problem,
but we have this message regularly:
08:28:44 Contiguous shared memory segment allocation failed at
0xb78ee000.
Allocation successful at 0x43800000.
Check SHMBASE is consistent with the value in
$INFORMIXDIR/etc/onconfig.std.
If you are using the correct SHMBASE value in your ONCONFIG file, then
consider this message informational only.
08:28:44 Dynamically allocated new virtual shared memory segment (size
8192KB)
08:28:44 Memory sizes:resident:1761624 KB, virtual:139872 KB, no
SHMTOTAL limit

Short extract from our onconfig-file:
SHMBASE 0x44000000L
SHMVIRTSIZE 32656
SHMADD 8192
EXTSHMADD 8192
SHMTOTAL 0
SHMVIRT_ALLOCSEG 0.000000
SHMNOACCESS

Can anybody help me or can give me an advice how to solve this problem?
Or is anybody experiencing similiar problems?

Thanks for reading my long post :-)
Klaus

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Messages In This Thread

• 11.5 UC7E crashes
  KLAUS GLAHN -- Tuesday, 20 December 2011, at 2:06 p.m.
  • RE: 11.5 UC7E crashes
    Joerg Volz -- Tuesday, 20 December 2011, at 2:58 p.m.
  • RE: 11.5 UC7E crashes
    Marcus Haarmann -- Wednesday, 21 December 2011, at 3:06 a.m.
  • Re: 11.5 UC7E crashes
    KLAUS GLAHN -- Wednesday, 21 December 2011, at 2:40 p.m.
    • Re: 11.5 UC7E crashes
      Art Kagel -- Wednesday, 21 December 2011, at 2:56 p.m.
      • Re: 11.5 UC7E crashes
        rroussey@comcast.net -- Wednesday, 21 December 2011, at 3:50 p.m.
        • Re: 11.5 UC7E crashes
          KLAUS GLAHN -- Wednesday, 21 December 2011, at 6:00 p.m.
    • Re: 11.5 UC7E crashes
      Joerg Volz -- Wednesday, 21 December 2011, at 2:58 p.m.
      • Re: 11.5 UC7E crashes
        KLAUS GLAHN -- Wednesday, 21 December 2011, at 5:50 p.m.
        • RE: 11.5 UC7E crashes
          Joerg Volz -- Wednesday, 21 December 2011, at 6:06 p.m.
        • Re: 11.5 UC7E crashes
          Art Kagel -- Wednesday, 21 December 2011, at 7:20 p.m.
        • Re: 11.5 UC7E crashes
          Khaled Bentebal -- Wednesday, 21 December 2011, at 10:04 p.m.
          • Re: 11.5 UC7E crashes
            Fernando Nunes -- Wednesday, 21 December 2011, at 10:28 p.m.
            • Re: 11.5 UC7E crashes
              Khaled Bentebal -- Thursday, 22 December 2011, at 7:26 a.m.
    • Re: 11.5 UC7E crashes
      Martin Fuerderer -- Thursday, 22 December 2011, at 5:17 a.m.
      • Re: 11.5 UC7E crashes
        Harshavardhan Changappa -- Thursday, 22 December 2011, at 6:37 a.m.
  • Re: 11.5 UC7E crashes
    KLAUS GLAHN -- Friday, 23 December 2011, at 6:51 a.m.
    • RE: 11.5 UC7E crashes
      Joerg Volz -- Friday, 23 December 2011, at 7:07 a.m.
      • Re: RE: 11.5 UC7E crashes
        KLAUS GLAHN -- Friday, 23 December 2011, at 9:55 a.m.
        • RE: Re: RE: 11.5 UC7E crashes
          Marcus Haarmann -- Friday, 23 December 2011, at 10:39 a.m.
  • Status
    KLAUS GLAHN -- Thursday, 29 December 2011, at 2:24 p.m.
    • crash again
      KLAUS GLAHN -- Wednesday, 4 January 2012, at 9:39 a.m.
      • RE: crash again
        Marcus Haarmann -- Wednesday, 4 January 2012, at 9:48 a.m.

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