kernel paramter for multiple oracle databases

[Greg Roberts]

Our new hp9000 running hp11 has 4GB's of memory but the old server with only 769MB seems to run mutliple databases better. My DBA wants to run like 12 large oracle databases. The memory usage reported by sam is only like 130-160 MB, no where near 4GB. I'm trying to get more memory usage to run more processes. Problem is I don't know what kernal paramters to increase to get more "usage". The values below are from our old server and from our internal oracle support. Since the old server was running some of these paramters I would think they could go higher, BUT WHICH????? Any suggestion appreicated.

Running like
maxfiles 2048
maxssiz 100 mb
maxuprc 512
nfile 11678
ninode 8772
nproc 4116
semmni 514
semmns 512
shmmax 1GB
shmmni 1024

[Kofi ARTHIABAH · Accepted solution]

I have a similar development server that runs 12 instances... here are the parameters I use (not that some of them are calculated... )

maxfiles 2048
maxfiles_lim 2048
maxusers 251
msgssz 256
msgtql (NPROC*10)
nfile (30*NPROC+2048)
nflocks (NPROC)
ninode (8*NPROC+2048)
nproc ((MAXUSERS*3)+64)
nstrpty 60
nstrtel (MAXUSERS)
semmni (NPROC*5)
semmns (SEMMNI*2)
semmnu (NPROC-4)
semume 64
semvmx 32768
shmmax 0X40000000
shmmni 1024
shmseg 128

[John Palmer]

Hi Greg,

I would start tuning the kernel by using the 'database server' template in SAM -> kernel configuration -> configurable parameters -> actions.

Then you need to revert a few:-

bufpages back to 0.
dbc_maxpct to a % of RAM that equals approx 256Mb.
swapmem_on back to 1.
timeslice back to 10.

Scroll through the values and compare the current and intended values.

Regards,
John

[Wade Satterfield]

I am suprised that maxdsiz didn't show up on your list of kernel parameters. The default value is 64M and Oracle knows not to try and exceed it. At 12 processes you won't use more than 768M.

How high to raise maxdsiz will depend a bit on how big your databases are. If they are all about the same size I would set maxdsiz to about 1/12th of your memory. If some are small and some are big I would make maxdsiz even bigger.