How is SWAP space and Oracle's Shared Memory related ?

Question

Platform: RHEL 5.4
Oracle Version: 11.2
I was trying to increase MEMORY_TARGET to 15g. Then I encountered the following error
SQL> alter system set memory_max_target=20g scope=spfile;
System altered.
SQL> alter system set memory_target=15g scope=spfile;
System altered.
SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL>
SQL>
SQL>
SQL> startup
ORA-32004: obsolete or deprecated parameter(s) specified for RDBMS instance
ORA-00845: MEMORY_TARGET not supported on this system
SQL>
SQL>
SQL> select name from v$database;
select name from v$database
ERROR at line 1:
ORA-01034: ORACLE not available
Process ID: 0
Session ID: 189 Serial number: 9From the below post
MEMORY_TARGET not supported on this system
I gathered that In Linux, if you want to set MEMORY_TARGET, MEMORY_MAX_TARGET to nGB , then you should have a SWAP ( /dev/shm ) of nGB.
My Swap was only 16gb and I was trying to set memory_max_target to 20g
$ df -h /dev/shm
Filesystem            Size  Used Avail Use% Mounted on
tmpfs                  16G  7.2G  8.6G  46% /dev/shmNow, I am wondering how is Oracle's Shared Memory (SGA+PGA) related to SWAP space in a server ? Shouldn't Oracle's Shared Memory be related to Physical RAM rather than disk based SWAP space ?

Answer 1

related question:
In the above mentioned OTN article it says ,
You could encounter ORA-00845 if your shared memory is not mapped to /dev/shm
I think he meant
You could encounter ORA-00845 if your SWAP space is not mapped to /dev/shm .
Am I right ?