SGA Swapping

[sudip]

Hi! All
Is there any method of knowing whether SGA is swapping or not? Platform is Sun os5.6.
Thanx

[pipo]

well, I do not have the answer to your question, what I know is that Oracle and Sun (as well as HP), do recommend that the SGA is at max 1/3 to 1/2 of physical memory, to avoid swapping ...

[sudip]

Hmmm.
I think I have some problem with unix kernel parameters. With Oracle down, the swap -s shows swapping.

[pipo]

what are the values of your Kerner SHM... and SEM ... parameters ??

[sudip]

set shmsys:shminfo_shmmax=1073741824
set shmsys:shminfo_shmmin=1
set shmsys:shminfo_shmmni=100
set shmsys:shminfo_shmseg=10
set semsys:seminfo_semmns=200
set semsys:seminfo_semmni=70
set semsys:seminfo_semmnu=64
set semsys:seminfo_semume=64

[dknight]

On Solaris 2.6 you can see the swap with the "top" commmand.

[pipo]

well, here is some info I have :
- to see if your SGA swaps, shutdown the DB, type vmstat 5, and look for freemem and available swap, then startup the DB, and just see if the available swap has decreased
- according to sun, here are some recommendations, sorry for the format

Name Reference Suggested
______ _________ __________
shmmax Maximum shm segment size in bytes 50 %of RAM
shmmin Minimum shm segment size in bytes 1
shmni Number of shm id to pre-allocate 100
shmseg Maximum number shm seg per process 32
semmni Number of semaphore identifiers 64
semmns Number of semaphores in system 1600
semmnu Number of undo structures in sys 1250
semmsl Maximum number of semaphores per ID 25

[sudip]

YEs my SGA is Swapping.
Thanx