Re: kernel/init parameters

From: Deepak Sharma <sharmakdeep_at_yahoo.com>
Date: Fri, 12 May 2000 13:04:37 -0700 (PDT)
Message-Id: <10495.105564@fatcity.com>

SGA = (db_block_buffers * db_block_size) +

       shared_pool_size +
       sort_area_size + 
       overhead

Going by this formula I have noted that the actual SGA size comes apprx the same as calculated here (value for 'overhead' varies, and I frankly don't know how to account for it - I normally keep it 10; no reason whatsoever). Also, assuming there will be just 1 instance on your m/c, based upon what I have read or heard:

o SGA should ideally be aroung 1/3rd of the physical RAM available (In your case 1/3rd of 3Gig). Check the SHMMAX (Is it 1/2 Gig right now ?)

o Shared Pool should be 1/5th to 1/6th of SGA

o The sort area size will depend upon the sorting requirements of the application. Keep default for now and adjust later on.

Working backwards from 1Gig SGA, calculate the following.

DB_BLOCK_BUFFERS	    218,437 (Calculated)
DB_BLOCK_SIZE	              4,096 (Can't change)
SORT_AREA_SIZE	             65,536 (sorts reqmnt)
SHARED_POOL_SIZE	178,956,971 (1/6th of 1GB)
-----------------------------------
SGA	              1,073,741,824 (1/3rd of RAM)
-----------------------------------

Also, since you have 6 cpus, adjust the db_block_lru_latches = 12 (Twice the no. of CPUs)

• Deepak Sharma
  • cemail_at_sprintmail.com wrote:
    >
    > I am getting ready to install Oracle on Solaris with
    > 3GB RAM/6
    > cpus. Can somebody please verify for me that these
    > kernel parameters
    > and init parameters will be okay? Any suggestions
    > for changing
    > these would be greatly appreciated. It will be a
    > large database.
    >
    > /etc/system:
    > set shmsys:shminfo_shmmax=512000000
    > set shmsys:shminfo_shmmin=1
    > set shmsys:shminfo_shmmni=512
    > set shmsys:shminfo_shmseg=128
    > set semsys:seminfo_semmns=1600
    > set semsys:seminfo_semmni=64
    > set semsys:seminfo_semmsl=500
    >
    > init:
    > db_block_size=4096 (cant be changed)
    > db_block_buffers =7168
    > shared_pool_size = 134217728
    > log_buffer=327680
    > processes=500
    > sort_write_buffer_size = 65536
    >
    >
    >
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Do You Yahoo!? Received on Fri May 12 2000 - 15:04:37 CDT