How to tune the kernel Configurable Parameters for sybase 11?

[MA Qiang]

OS: HP 11iv1
Memory: 8GB
CPU: 4

Thanks!

[harry d brown jr]

You usually get this information from SYBASE, as we do for ALL other products (Oracle, Informix, BEA, ...).

Then once armed with that info, you can use "sam"->Kernel Configuration->configure kernel

live free or die
harry d brown jr

[Eric Antunes]

Hi Qiang,

You should have from 300-400 Mb buffer cache:

dbc_max_pct = 5
dbc_min_pct = 3

More things you can check with "sar -v 5 1000" (see if one of the following parameters overflows):

ninode = 2048 (2048 it's a good start)
nproc = 400 (an idea -> depends of db and apps)
nfile = (15*nproc+2048)

Kindest Regards,

Eric Antunes


swchunk = 4096

[Steven E. Protter]

1) Go to the documentation for sybase.
2) Get the minimum kernel parameters for Sybase.

Use this methodology to set parameters and put a new kernel into production.

You can also use sam.


kmtune -s parameter=####

# use a real parameter and a real number based on your current kmtune output and the documentation on sybase.


#cd /stand
#cp vmunix vmunix.old
#cp system system.old
#cd build

#this is the changed line.
#/usr/lbin/sysadm/system_prep -s system

Edit system file and make changes here as per ur require ment. Imeand addition/Deletion of devices. Then
#mk_kernel -s system
For more information see the man page of mk_kernel

Now one new kernel will be created in /stand/build directory. Copy this to original location
#cd /stand/build
#cp vmunix_test /stand/vmunix
#cp system /stand


Sorry I can't help you with the Sybase doc, I'm assuming you can find that yourself.

SEP

[Eric Antunes · Accepted solution]

Some specific threads about sysbase:

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=204085

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=77268

Eric

[MA Qiang]

I got the following error when I issued the isql.
sybase@mercury2 [/opt/sybase/install]
> isql -Usa
/usr/lib/dld.sl: Call to mmap() failed - TEXT /usr/lib/libcl.1
/usr/lib/dld.sl: Not enough space
Abort(coredump)

[Eric Antunes]

Hi,

I think you'll have to tune all the kernel.

Here are my tuned parameters (non default):

STRMSGSZ 65535
dbc_max_pct 15
dbc_min_pct 10
max_async_ports 206
max_thread_proc 256
maxdsiz 536870912
maxfiles 1024
maxssiz 134217728
maxssiz_64bit 1073741824
maxswapchunks 16384
maxtsiz 134217728
maxuprc (NPROC*9/10)
maxusers 150
msgmap (2+MSGMNI)
msgmni (NPROC)
msgseg 32767
msgtql (NPROC)
nfile (15*NPROC+2048)
nflocks 4096
ninode 2048
nproc 400
nstrpty 60
num_tachyon_adapters 5
semmni 4096
semmns (SEMMNI*2)
semmnu (NPROC-4)
shmmax 1073741824 (Max Shared Mem Segment (Bytes): this is a memory dependent parameter so, since you have 5 times the memory I've, you can multiply this value by 5: 5368709120
shmmni 512
swchunk 4096
vps_ceiling 64

See if you have big differences at those parameters values and try to approach to my values.

Finally, since you are on 11i v1 (I'm on 11.0) you may have to tune other new parameters (not present on 11.0)

Best Regards,

Eric Antunes

[MA Qiang]

I issued "chatr -M /opt/sybase/bin/dataserver", and let sybase fit on quadrant 2 of shared memory.
Then solved the problem.
Are there any disadvantages for sybase performance when it is running on quadrant 2?

[Eric Antunes]

I don't know the answer to this question. What is quadrant 2 of shared memory??

[MA Qiang]

My sybase is 32-bit version. Use chatr -M can fit the 32-bit application on Q2 of shared memory. You can man the chatr for SHMEM-MAGIC.