I'm posting this to CDI and the Linux List for Julia who's having a problem the
list may be able to help with. Please include her address (below) in you reply:

Art S. Kagel
----- Original Message -----
From: Julia M <juliamrus@YAHOO.COM>
At: 10/ 5 22:25
<SNIP>
I am trying to increase shared memory setting on our
server running on a DELL poweredge 6650 with 4GB RAM
and linux 2.4 (enterprise).
For some reason if I set the buffers value to anything
morethan 700000 it crashed saying can't allocate
shared memory.
Here I don't want to increase the Virtual segment but
the Buffers.

I tried the following SHMMAX values but Informix
doesn't seems to like any of the values set through
sysctl.conf during the server bootup.


#kernel.shmmax = 33554432 - release note value
#kernel.shmmax = 134217728
#kernel.shmmax = 2*536870912
(all above values failed with more than 700000
buffers)

SHMBASE 0x50000000 # Shared memory base
address in onconfig -
(release note says this should be set to 0x1000000L.
But when you do that you can't allocate shared memory
more than 700 MB)


kernel.shmmax = 536870912 (current value)
kernel.shmmin = 1
kernel.shmmni = 128
kernel.shmseg = 128
kernel.semmns = 4096
kernel.semmnu = 4096
kernel.semume = 32
kernel.semmap = 4096
kernel.semmsl = 100



I have no clue why It can't go beyond the shared
memeory value of 1896000 KB (When buffers value set
above 700000).
What am I missing here??
Any answer to this is much appreciated.

I have included the cat /proc/meminfo, onconfig and
online.log values for you to
get an idea.


cat /proc/meminfo
total: used: free: shared: buffers:
cached:
Mem: 3692048384 2287001600 1405046784 1521373184
107352064 151183360
Swap: 2146754560 0 2146754560
MemTotal: 3605516 kB
MemFree: 1372116 kB
MemShared: 1485716 kB
Buffers: 104836 kB
Cached: 147640 kB
SwapCached: 0 kB
Active: 136932 kB
Inact_dirty: 1601260 kB
Inact_clean: 0 kB
Inact_target: 917488 kB
HighTotal: 2752448 kB
HighFree: 699988 kB
LowTotal: 853068 kB
LowFree: 672128 kB
SwapTotal: 2096440 kB
SwapFree: 2096440 kB
BigPagesFree: 0 kB



Informix Dynamic Server Version 7.31.UD6 --
On-Line -- Up 09:23:06 -- 1896196 Kbytes

Configuration File: /usr/informix/etc/onconfig.malco
#************************************************* *************************
#
# INFORMIX SOFTWARE, INC.
#
# Title: onconfig.std
# Description: Informix Dynamic Server Configuration
Parameters
#
#************************************************* *************************

# Root Dbspace Configuration

ROOTNAME rootdbs # Root dbspace name
ROOTPATH /usr/informix/data/db01
# Path for device
containing root dbspace
ROOTOFFSET 2 # Offset of root
dbspace into device (Kbytes)
ROOTSIZE 1048576 # Size of root dbspace
(Kbytes)

# Disk Mirroring Configuration Parameters

MIRROR 0 # Mirroring flag (Yes
= 1, No = 0)
MIRRORPATH # Path for device
containing mirrored root
MIRROROFFSET 0 # Offset into mirrored
device (Kbytes)

# Physical Log Configuration

PHYSDBS plogdbs # Location (dbspace)
of physical log
PHYSFILE 262140 # Physical log file
size (Kbytes)

# Logical Log Configuration

LOGFILES 510 # Number of logical
log files
LOGSIZE 1024 # Logical log size
(Kbytes)

# Diagnostics

MSGPATH /var/informix/online.log # System
message log file path
CONSOLE /dev/tty1 # System console
message path
ALARMPROGRAM /usr/informix/etc/log_full.sh # Alarm
program path
SYSALARMPROGRAM /usr/informix/etc/evidence.sh # System
Alarm program path
TBLSPACE_STATS 1

# System Archive Tape Device

TAPEDEV /dev/vm0 # Tape device path
#TAPEDEV /dev/null # Tape device path
TAPEBLK 512 # Tape block size
(Kbytes)
TAPESIZE 100000000 # Maximum amount of
data to put on tape (Kbytes)

# Log Archive Tape Device

LTAPEDEV /dev/vm0 # Log tape device path
#LTAPEDEV /dev/null # Log tape device
path
LTAPEBLK 512 # Log tape block size
(Kbytes)
LTAPESIZE 100000000 # Max amount of data
to put on log tape (Kbytes)

# Optical

STAGEBLOB # Informix Dynamic
Server/Optical staging area

# System Configuration

SERVERNUM 1 # Unique id
corresponding to a Dynamic Server instance
DBSERVERNAME malco_1 # Name of default
database server
DBSERVERALIASES malco_2,mallive # List of
alternate dbservernames
NETTYPE ipcshm,5,50,CPU # Configure poll
thread(s) for nettype
NETTYPE soctcp,2,25,NET # Configure poll
thread(s) for nettype
DEADLOCK_TIMEOUT 30 # Max time to wait of
lock in distributed env.
RESIDENT 1 # Forced residency
flag (Yes = 1, No = 0)

MULTIPROCESSOR 1 # 0 for
single-processor, 1 for multi-processor
NUMCPUVPS 7 # Number of user (cpu)
vps
SINGLE_CPU_VP 0 # If non-zero, limit
number of cpu vps to one

NOAGE 0 # Process aging
AFF_SPROC # Affinity start
processor
AFF_NPROCS # Affinity number of
processors

# Shared Memory Parameters

#LOCKS 65536 # Maximum number of
locks
LOCKS 250000
BUFFERS 648216 # Maximum number of
shared buffers
NUMAIOVPS 16 # Number of IO vps
PHYSBUFF 96 # Physical log buffer
size (Kbytes)
LOGBUFF 32 # Logical log buffer
size (Kbytes)
LOGSMAX 512 # Maximum number of
logical log files
CLEANERS 108 # Number of buffer
cleaner processes
SHMBASE 0x50000000 # Shared memory base
address
SHMVIRTSIZE 262144 # initial virtual
shared memory segment size
SHMADD 65536 # Size of new shared
memory segments (Kbytes)
SHMTOTAL 2048000 # Total shared memory
(Kbytes). 0=>unlimited
CKPTINTVL 300 # Check point interval
(in sec)
LRUS 128 # Number of LRU queues
LRU_MAX_DIRTY 2 # LRU percent dirty
begin cleaning limit
LRU_MIN_DIRTY 1 # LRU percent dirty
end cleaning limit
LTXHWM 40 # Long transaction
high water mark percentage
LTXEHWM 60 # Long transaction
high water mark (exclusive)
TXTIMEOUT 0x12c # Transaction
timeout (in sec)
STACKSIZE 32 # Stack size (Kbytes)

# System Page Size
# BUFFSIZE - Dynamic Server no longer supports this
configuration parameter.
# To determine the page size used by
Dynamic Server on your platform
# see the last line of output from the
command, 'onstat -b'.


# Recovery Variables
# OFF_RECVRY_THREADS:
# Number of parallel worker threads during fast
recovery or an offline restore.
# ON_RECVRY_THREADS:
# Number of parallel worker threads during an online
restore.

OFF_RECVRY_THREADS 10 # Default number of
offline worker threads
ON_RECVRY_THREADS 1 # Default number of
online worker threads

# Data Replication Variables
# DRAUTO: 0 manual, 1 retain type, 2 reverse type
DRAUTO 0 # DR automatic
switchover
DRINTERVAL 30 # DR max time between
DR buffer flushes (in sec)
DRTIMEOUT 30 # DR network timeout
(in sec)
DRLOSTFOUND /usr/informix/etc/dr.lostfound # DR
lost+found file path

# CDR Variables
CDR_LOGBUFFERS 2048 # size of log reading
buffer pool (Kbytes)
CDR_EVALTHREADS 1,2 # evaluator threads
(per-cpu-vp,additional)
CDR_DSLOCKWAIT 5 # DS lockwait timeout
(seconds)
CDR_QUEUEMEM 4096 # Maximum amount of
memory for any CDR queue (Kbytes)

# Backup/Restore variables
BAR_ACT_LOG /tmp/bar_act.log
BAR_MAX_BACKUP 0
BAR_RETRY 1
BAR_NB_XPORT_COUNT 10
BAR_XFER_BUF_SIZE 31

# Informix Storage Manager variables
ISM_DATA_POOL ISMData # If the data pool
name is changed, be sure to
# update $INFORMIXDIR/bin/onbar. Change to
# ism_catalog -create_bootstrap -pool <new name>
ISM_LOG_POOL ISMLogs

# Read Ahead Variables
RA_PAGES # Number of pages to
attempt to read ahead
RA_THRESHOLD # Number of pages left
before next group

# DBSPACETEMP:
# Dynamic Server equivalent of DBTEMP for SE. This is
the list of dbspaces
# that the Dynamic Server SQL Engine will use to
create temp tables etc.
# If specified it must be a colon separated list of
dbspaces that exist
# when the Dynamic Server system is brought online.
If not specified, or if
# all dbspaces specified are invalid, various ad hoc
queries will create
# temporary files in /tmp instead.

DBSPACETEMP tem1dbs,tmp2dbs,tmp3dbs,tmp4dbs #
Default temp dbspaces

# DUMP*:
# The following parameters control the type of
diagnostics information which
# is preserved when an unanticipated error condition
(assertion failure) occurs
# during Dynamic Server operations.
# For DUMPSHMEM, DUMPGCORE and DUMPCORE 1 means Yes, 0
means No.

DUMPDIR /tmp # Preserve diagnostics
in this directory
DUMPSHMEM 1 # Dump a copy of
shared memory
DUMPGCORE 0 # Dump a core image
using 'gcore'
DUMPCORE 0 # Dump a core image
(Warning:this aborts Dynamic Server)
DUMPCNT 1 # Number of shared
memory or gcore dumps for
# a single user's session

FILLFACTOR 90 # Fill factor for
building indexes

# method for Dynamic Server to use when determining
current time
USEOSTIME 0 # 0: use internal
time(fast), 1: get time from OS(slow)

# Parallel Database Queries (pdq)
MAX_PDQPRIORITY 80 # Maximum allowed
pdqpriority
DS_MAX_QUERIES # Maximum number of
decision support queries
DS_TOTAL_MEMORY # Decision support
memory (Kbytes)
DS_MAX_SCANS 1048576 # Maximum number of
decision support scans
DATASKIP off # List of dbspaces to
skip

# OPTCOMPIND
# 0 => Nested loop joins will be preferred (where
# possible) over sortmerge joins and hash joins.
# 1 => If the transaction isolation mode is not
# "repeatable read", optimizer behaves as in (2)
# below. Otherwise it behaves as in (0) above.
# 2 => Use costs regardless of the transaction
isolation
# mode. Nested loop joins are not necessarily
# preferred. Optimizer bases its decision purely
# on costs.
OPTCOMPIND 2 # To hint the
optimizer

ONDBSPACEDOWN 2 # Dbspace down option:
0 = CONTINUE, 1 = ABORT, 2 = WAIT
LBU_PRESERVE 1 # Preserve last log
for log backup
OPCACHEMAX 0 # Maximum optical
cache size (Kbytes)

# HETERO_COMMIT (Gateway participation in distributed
transactions)
# 1 => Heterogeneous Commit is enabled
# 0 (or any other value) => Heterogeneous Commit is
disabled
HETERO_COMMIT 0

# Optimization goal: -1 = ALL_ROWS(Default), 0 =
FIRST_ROWS
OPT_GOAL -1

# Optimizer DIRECTIVES ON (1/Default) or OFF (0)
DIRECTIVES 1

# Status of restartable restore
RESTARTABLE_RESTORE off
CDR_LOGDELTA 30 # % of log space
allowed in queue memory
CDR_NUMCONNECT 16 # Expected connections
per server
CDR_NIFRETRY 300 # Connection retry
(seconds)
CDR_NIFCOMPRESS 0 # Link level
compression (-1 never, 0 none, 9 max)
BAR_DEBUG_LOG /tmp/bar_dbug.log # ON-Bar Debug Log -
not in /tmp please


================================================== ==============================
========

This is what happened when I try to increase the
number of buffers beyond=700000


04:30:03 Informix Dynamic Server Stopped.

04:36:37 Segment locked: addr=0x50000000,
size=1692237824
04:36:37 Segment locked: addr=0x50000000,
size=1692237824
04:36:37 Segment locked: addr=0x50000000,
size=1692237824
04:36:37 Segment locked: addr=0x50000000,
size=1692237824
04:36:37 Segment locked: addr=0x50000000,
size=1692237824
04:36:37 Segment locked: addr=0x50000000,
size=1692237824
04:36:37 Segment locked: addr=0x50000000,
size=1692237824
04:36:37 Segment locked: addr=0x50000000,
size=1692237824
04:36:37 Segment locked: addr=0x50000000,
size=1692237824
04:36:37 Segment locked: addr=0x50000000,
size=1692237824
04:36:37 Segment locked: addr=0x50000000,
size=1692237824
04:36:37 Segment locked: addr=0x50000000,
size=1692237824
04:36:37 Segment locked: addr=0x50000000,
size=1692237824

Fri Sep 10 04:36:38 2004

04:36:38 Assert Failed: Internal error: embedded
mutex, name = support

04:36:38 Informix Dynamic Server Version 7.31.UD6
04:36:38 Who: Session(0, @, 0, 0)
Thread(1, main_thread, 0, 1)
File: mt.c Line: 6532
04:36:39 See Also: /tmp/af.3e9a2b6, shmem.3e9a2b6.0
04:36:42 Error writing '/tmp/shmem.3e9a2b6.0' errno =
14
04:36:42 mt.c, line 6532, thread 1, proc id 1417,
Internal error: embedded mutex, name = support
04:36:42 PANIC: Attempting to bring system down





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sending to informix-list

ART KAGEL, BLOOMBERG/ 499 PARK wrote:

> I'm posting this to CDI and the Linux List for Julia who's having a problem the
> list may be able to help with. Please include her address (below) in you reply:

Nope - there's the IIUG archive, and there's groups.google.com, ...


> ----- Original Message -----
> From: Julia M <juliamrus@YAHOO.COM>
> At: 10/ 5 22:25
> <SNIP>
> I am trying to increase shared memory setting on our
> server running on a DELL poweredge 6650 with 4GB RAM
> and linux 2.4 (enterprise).
> For some reason if I set the buffers value to anything
> morethan 700000 it crashed saying can't allocate
> shared memory.
> Here I don't want to increase the Virtual segment but
> the Buffers.

You're on a 32-bit system (IDS 7.31.UD6). You won't get to all 4 GB
available as buffers in a single IDS instance because a 32-bit system
only has 4 GB total memory, and some of that has to be used for the
code, shared libraries, and per-process (as opposed to per-thread)
stack and heap space. You might, perhaps, reach 3GB; you'll be hard
pushed to reach much more.

The next problem is the way that Linux places shared libraries in
memory -- be grateful you aren't using RHEL v3 update 3 with its
Exec-Guard and randomized mapping (hi Ron!).

Basically, you need to have a 3GB gap in the memory map available to
allocate your 3 GB chunk of shared memory. I'm not clear on all the
ins and outs of how you do that, but you need to ensure that shared
libraries are loaded at a high enough address and SHMBASE is set low
enough that there is a 3GB gap available to use. (One reason why its
going to be hard to use more than 3 GB is that there's even less room
for manoeuvre as you increase the space allocated to shared memory.

> I tried the following SHMMAX values but Informix
> doesn't seems to like any of the values set through
> sysctl.conf during the server bootup.
>
>
> #kernel.shmmax = 33554432 - release note value
> #kernel.shmmax = 134217728
> #kernel.shmmax = 2*536870912
> (all above values failed with more than 700000
> buffers)
>
> SHMBASE 0x50000000 # Shared memory base
> address in onconfig -
> (release note says this should be set to 0x1000000L.
> But when you do that you can't allocate shared memory
> more than 700 MB)
>
>
> kernel.shmmax = 536870912 (current value)
> kernel.shmmin = 1
> kernel.shmmni = 128
> kernel.shmseg = 128
> kernel.semmns = 4096
> kernel.semmnu = 4096
> kernel.semume = 32
> kernel.semmap = 4096
> kernel.semmsl = 100
>
>
>
> I have no clue why It can't go beyond the shared
> memeory value of 1896000 KB (When buffers value set
> above 700000).
> What am I missing here??
> Any answer to this is much appreciated.
>
> I have included the cat /proc/meminfo, onconfig and
> online.log values for you to
> get an idea.
>
>
> cat /proc/meminfo
> total: used: free: shared: buffers:
> cached:
> Mem: 3692048384 2287001600 1405046784 1521373184
> 107352064 151183360
> Swap: 2146754560 0 2146754560
> MemTotal: 3605516 kB
> MemFree: 1372116 kB
> MemShared: 1485716 kB
> Buffers: 104836 kB
> Cached: 147640 kB
> SwapCached: 0 kB
> Active: 136932 kB
> Inact_dirty: 1601260 kB
> Inact_clean: 0 kB
> Inact_target: 917488 kB
> HighTotal: 2752448 kB
> HighFree: 699988 kB
> LowTotal: 853068 kB
> LowFree: 672128 kB
> SwapTotal: 2096440 kB
> SwapFree: 2096440 kB
> BigPagesFree: 0 kB
>
> Informix Dynamic Server Version 7.31.UD6 --
> On-Line -- Up 09:23:06 -- 1896196 Kbytes
>
> Configuration File: /usr/informix/etc/onconfig.malco
>[...]

> ================================================== ================
>
> This is what happened when I try to increase the
> number of buffers beyond=700000
>
>
> 04:30:03 Informix Dynamic Server Stopped.
>
> 04:36:37 Segment locked: addr=0x50000000,
> size=1692237824
>[...]
> 04:36:37 Segment locked: addr=0x50000000,
> size=1692237824
>
> Fri Sep 10 04:36:38 2004
>
> 04:36:38 Assert Failed: Internal error: embedded
> mutex, name = support
>
> 04:36:38 Informix Dynamic Server Version 7.31.UD6
> 04:36:38 Who: Session(0, @, 0, 0)
> Thread(1, main_thread, 0, 1)
> File: mt.c Line: 6532
> 04:36:39 See Also: /tmp/af.3e9a2b6, shmem.3e9a2b6.0
> 04:36:42 Error writing '/tmp/shmem.3e9a2b6.0' errno =
> 14
> 04:36:42 mt.c, line 6532, thread 1, proc id 1417,
> Internal error: embedded mutex, name = support
> 04:36:42 PANIC: Attempting to bring system down


--
Jonathan Leffler #include <disclaimer.h>
Email: jleffler@earthlink.net, jleffler@us.ibm.com
Guardian of DBD::Informix v2003.04 -- http://dbi.perl.org/