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Set shmmax to 2.75 GB on HP-UX 10.20'

Set shmmax to 2.75 GB on HP-UX 10.20'

Hi,

Hardware: K370
Memory : 2.5 GB + Swap ( 5 GB )

I need to change the maximun size of shmmax kernel parameter to 2.75 GB.

I know wich it is possible, but I don?t remember.

I remember this steps:

1. Change the /usr/conf/master.d/core-hpux file
in line:
.
.
core-hpux:shmmax SHMMAX 0X4000000
.
.

2. Generete the new kernel
- backup the system and vmunix files
- change the system file :
shmmax 0x9C400000 ( 2.5 GB )
- reboot the system


Do you know if this steps are correctily?

Thank?s

Andre Machado
3 REPLIES
Thierry Poels_1
Honored Contributor

Re: Set shmmax to 2.75 GB on HP-UX 10.20'

Hi Andre,

how about using SAM to modify the kernel parameter?? Safe & Easy ;-)

good luck,
Thierry.
All unix flavours are exactly the same . . . . . . . . . . for end users anyway.
Wodisch
Honored Contributor

Re: Set shmmax to 2.75 GB on HP-UX 10.20'

Hello Andre,

AFAIK the maximum per SINGLE shared memory segment
is still 1GB, not 2.5GB, but with some EXEC_MAGIC tricks
you may have up to 2.75GB in TOTAL (i.e. using multiple
segments). So you will need some linker-commands, or
"chatr" (on HPUX11) and similiar...

Just my ?0.02,
Wodisch
linuxfan
Honored Contributor

Re: Set shmmax to 2.75 GB on HP-UX 10.20'

Hi Andre,

You might want to look at
1. HP Doc A5013893 ( on how to increase the shmmax
http://us-support2.external.hp.com/cki/bin/doc.pl/sid=4e7ec34a13487e2562/screen=ckiDisplayDocument?docId=200000024645549
/Begin/
Use the procedure below to increase shared memory. On a series 800
with HP-UX 10.20, you may access 2.75 GB of shared memory. In that
case, you obtain 2.75 GB with 3 segments:

- 1 GB, 24 KB (quadrant 2)
- 1 GB (quadrant 3)
- 0.75 GB (quadrant 4)

Here are the steps to properly increase
shared memory on your system:

1. Install following patches:

- PHSS_10926
- PHCO_10924
- PHKL_11086
- PHKL_12410

Note: Patches can be superseded by subsequent versions;
be sure to load the current version.

2. Execute chatr -M

3. Increase shmmax (increase by increments of 20).

4. Increase maxdsiz and maxtsiz to correspond to shmmax,
and increase maxssiz proportionally.

5. Regenerate the kernel.

/End/


Also you may want to check out
2. HP Doc RCMEMKBAN00000027 (Understanding Shared memory on PA-RISC systems)
http://us-support2.external.hp.com/cki/bin/doc.pl/sid=43619d621127498fed/screen=ckiDisplayDocument?docId=200000045618004

3. Another document you might find handy is Doc KBAN00000275
http://us-support2.external.hp.com/cki/bin/doc.pl/sid=43619d621127498fed/screen=ckiDisplayDocument?docId=200000048391472

-HTH
Ramesh
They think they know but don't. At least I know I don't know - Socrates