SEMVMX

Maximum value of a semaphore.

Recommended:

>= Oracle 9i = 32768

shmmax (see appendix 4)

maximum allowable size of one shared memory

segment. The SHMMAX setting should be large

enough to hold the entire SGA in one shared memory segment. A low setting can cause creation of multiple shared memory segments which may lead to performance degradation, but normally it is ok to use a small number of shared memory segments.

default=0x04000000 (64MB) Oracle 7

             0x40000000 (1GB =  1073741824 Bytes) 

             Oracle 8, 8i, 9i

recommended:

db_block_size * db_block_buffers

+ shared_pool_size

+ log_buffer

+ shared memory for the application

or

hold the entire SGA in one shared memory segment !

(for 64bit use up to size of physical memory,

 but Oracle can also use multiple segments (please check appendix 4))

Shmmni

maximum number of shared memory segments in the entire system.

default=200.

 recommended:

<= Oracle 8.1.7 = use default.

>= Oracle 9i = 512

Shmseg

maximum number of shared memory segments one process can attach.

default=12.

recommended:

<= Oracle 8.1.7 = 10 per Oracle database

>= Oracle 9i = 32 per Oracle database

Streampipes

Set this parameter to 0 during on the installation of Oracle DB will reduce the installation time.

Default: 0

Recommended for installation: 0

swapmem_on

(see appendix 5)

Allow Memory to Exceed Swap Space

default: 0 (off)

recommended: 1 (on)

Swchunk

Swap Chunk Size (1K Blocks)

(related to kernel parameter maxswapchunks)

default: 2048

recommended: 4096 (up to 65536 for large RAM)

VPS_CEILING

maximum System-Selected Page Size in kilobytes.

Recommended:

>= Oracle9i =  64 (up to 16384 = 16MB for large SGA)