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Kernel Parameters Tuning for DB2 in HPUX 11.23i

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Kernel Parameters Tuning for DB2 in HPUX 11.23i

Dear HP-UX Gurus,
I would like to tune these km values for nflocks, msgmnb, msgmax,shmmax,shmmni in HP-UX 11.23i itanium 64bits.
do i need to reboot the server after change it? which is the safest way to change kernel values? hope to hear from you. many thanks in advance
4 REPLIES
Honored Contributor Honored Contributor

Re: Kernel Parameters Tuning for DB2 in HPUX 11.23i

Hello,

It all depends on whether the tunable
parameter is dynamic or not. In other words,
you need to check if a change can happen without a reboot.

Let's pick up one of your tunables:

# kctune -v shmmax

The system shows:

Tunable shmmax
Description Maximum size of a shared memory segment (bytes)
Module sysv_shm
Current Value 1073741824 [Default]
Value at Next Boot 1073741824 [Default]
Value at Last Boot 1073741824
Default Value 1073741824
Constraints shmmax >=3D 2048
shmmax <=3D 4398046511104
Can Change Immediately or at Next Boot

Look for "Can Change" row. Therefore,
shmmax can be changed without the reboot.

To change, you can use SAM or SMH interface,
or command-line (I prefer it):

# kctune shmmax=...

As an exercise, it is left for you
to chech the other tunables.

Regards,

VK2COT
VK2COT - Dusan Baljevic
Super Advisor

Re: Kernel Parameters Tuning for DB2 in HPUX 11.23i

oh thank you.
how about this? Automatic Tuning Enabled, does it require reboot?
lily:/>kctune -v nflocks
Tunable nflocks
Description Maximum number of file locks
Module fs
Current Value 4096 [Default]
Value at Next Boot Default (automatic)
Value at Last Boot 4096
Default Value 4096 (automatic)
Constraints nflocks >= 50
nflocks <= 16777216
Can Change Automatic Tuning Enabled
Acclaimed Contributor Acclaimed Contributor

Re: Kernel Parameters Tuning for DB2 in HPUX 11.23i

>how about this? Automatic Tuning Enabled, does it require reboot?
# kctune -v nflocks

Just look at the man page:
http://docs.hp.com/en/B2355-60103/nflocks.5.html
This tunable is dynamic
Honored Contributor Honored Contributor

Re: Kernel Parameters Tuning for DB2 in HPUX 11.23i

Hello,

nflocks tunable is dynamic (tuning will take
effect immediately on the running system).

When the value of nflocks is dynamically tuned
it cannot be set to a value lower than the
current number of file locks in the running
kernel.

Cheers,

VK2COT
VK2COT - Dusan Baljevic