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HPUX 11.11 tunable kernal parameters for HPUX 11.11

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Naveej.K.A
Honored Contributor

HPUX 11.11 tunable kernal parameters for HPUX 11.11

Hello all,

We have got a RP 5470 running HPUX 11i with a oracle 7.3 database. Recently due to an migration of an application from an old server, the number of concurrent users logged in has increased and has slowed down the system drastically. I doubt on some of the Oracle related tuable kernel parameters which has never been set. Can i get a list of those parameters and their recommended values.

Thanks in Advance

Naveej
practice makes a man perfect!!!
5 REPLIES
Ravi_8
Honored Contributor

Re: HPUX 11.11 tunable kernal parameters for HPUX 11.11

Hi,

Increasing 'nstrtel' and 'nproc' parameters may help u.
never give up
Indira Aramandla
Honored Contributor

Re: HPUX 11.11 tunable kernal parameters for HPUX 11.11

Hi Naveej,

The following table documents Unix kernel parameters that should be monitored and possibly increased after changes are made to the related init.ora parameter.

Init.ora Parameter Unix Kernel Parameter
db_block_buffers shmmax
db_files maxdatafiles) nfile,
maxfiles
large_pool_size shmmax
log_buffer shmmax
processes nproc, semmsl, semmns
shared_pool_size shmmax

As you have more number of concurrent users now, you will be set the process and sessins parameter and may be you want to make sure that the parameters related to number of processes (nproc) and the number of file descriptors as well.

The following Kernel Parameters tend to be generic

maxfiles - Soft file limit per process.
maxuprc - Maximum number of simultaneous user processes per userid.
nfile - Maximum number of simultaneously open files systemwide at any given time.
nproc - Maximum number of processes that can exist simultaneously in the system.
shmmax - The maximum size(in bytes) of a single shared memory segment.
shmmin - The minimum size(in bytes) of a single shared memory segment.
shmmni - The number of shared memory identifiers.
shmseg - The maximum number of shared memory segments that can be attached by a process.
semmns - The number of semaphores in the system.
semmni - The number of semaphore set identifiers in the system; determines the number of semaphore sets that can be created at any one time.
semmsl - The maximum number of sempahores that can be in one semaphore set. It should be same size as maximum number of Oracle processes.



Never give up, Keep Trying
Tim Adamson_1
Honored Contributor

Re: HPUX 11.11 tunable kernal parameters for HPUX 11.11

You may need to add more swap too. More users means more processes which means more swap reservation.

Why not post your system file and swapinfo -tam output. And provide an estimate on average number of concurrent users.


Tim
Yesterday is history, tomorrow is a mystery, today is a gift. That's why it's called the present.
Naveej.K.A
Honored Contributor

Re: HPUX 11.11 tunable kernal parameters for HPUX 11.11

Please find attached the file system.txt which is /stand/system file and the end if the file has the output of swapinfo -tam.

Thanks and regards

Naveej
practice makes a man perfect!!!
Tim Adamson_1
Honored Contributor
Solution

Re: HPUX 11.11 tunable kernal parameters for HPUX 11.11

I can see one major problem.

You have explicitly set nbuf to 6552. This means you have a buffer cache of about 25Mb. No wonder performance sucks.

Remove that line from the system file.

Add dbc_max_pct and set it to 15 (for a start anyway).

nflocks also looks small in comparison to nfile.

You will need to regenerate the kernel and reboot.

Performance will improve.


Tim
Yesterday is history, tomorrow is a mystery, today is a gift. That's why it's called the present.