Summary: Where do you set the shared memory variables.

From: MacDonell, Dennis <DennisMacDonell_at_auslig.gov.au>
Date: Thu, 28 Jun 2001 14:48:55 +1000

Hi,

If you are looking for information in the man pages on shared memory or
stacks, forget it. Even the man on dxkerneltuner does not outline what
variables may be set or what effect they might have. There were a few
summaries in my collection that referenced stack overflow (my original
problem with running Oracle srvmgrl). However, all the summaries had errors
in them, either not mentioning that the place where these variables are set
is in /etc/sysconfigtab (which it turns out can be managed by dxkerneltuner)
or had miss-spellings of variable names (mostly _ replaced by - chars or the
_ just omitted) or even one summary which had a variable name that didn't
seem to be the munged name for any existing variable (maybe that was a Tru64
version thing). Anyway, cutting and pasting from emails to /etc/sysconfigtab
may not solve peoples problems.

I'm not sure of the total ramifications of my actions, but this is what I
modified part of my /etc/sysconfigtab to look like (I only used
dxkerneltuner to find out the correct spelling of the variable names and
their section location) -

proc:
        maxusers=256
        max_per_proc_address_space=42924967296
        max_per_proc_data_size=42924967296
        max_proc_per_user=2048
        max_threads_per_user=2048
        per_proc_data_size=42924967296
        per_proc_stack_size=33554432
        per_proc_address_space=42924967296

ipc:
        shm_max=2139095040
        shm_min=1
        shm_mni=256
        shm_seg=32

Then after a reboot, I was then able to run the create_db.sh script for my
Oracle 8.1.5 database.

Dennis

Thanks to:
(a) Roetman, Paul [PRoetman_at_CSXLines.com] whose reply is included
Yes, you are correct, the ipc parameters recommended by oracle are
(something like) below.

Other interesting commands are
        ipcs -mcbpt
and
        login into oracle using svrmgrl
        show sga

The proc parameters also become important when you start to get larger
shared memory segments.

My ipc and process parameters (for ver5.0a) are:
proc:
        max-per-proc-address-space=42924967296
        max_per_proc_data_size=42924967296
        max_proc_per_user=2048
        max_threads_per_user=2048
        per-proc-data-size=42924967296
        per_proc_stack_size=33554432
        per_proc_address_space=42924967296


ipc:
        shm-max=2139095040
        shm-min=1
        shm-mni=256
        shm-seg=32
(b) Riggs, Joan [JRiggs_at_kls.usaka.smdc.army.mil] whose reply was
Using dxkerneltuner, see the IPC section to change these variables.
(c) John Tan [John.Tan_at_asx.com.au] whose reply was
Sounds right from the things I have done.

The original question:
Hi,

I'm running 5.0A and have come up against an Oracle problem. The error
message looks like -

Stack overflow: pid 4291, proc oracle, addr 0x11f7ffff0, pc 0x3ff801bc8c4

I noticed in a summary that you can overcome this by increasing shared
memory to a whopping 256gb, but the summary didn't spell where you set the
parameters. My guess is that its in the file /etc/sysconfigtab and the entry
should look like

ipc:
        SHMMAX 2139095040
        SHMMIN 1
        SHMMNI 100
        SHMSEG 32

Can anyone confirm this.

######################################
Dennis Macdonell
Systems Administrator
AUSLIG
mail: PO Box 2, Belconnen, ACT 2617
email: mcdonell_at_auslig.gov.au
ph: 61 2 6201 4326
fax: 61 2 6201 4377
######################################
Received on Thu Jun 28 2001 - 04:50:34 NZST

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